tag:theconversation.com,2011:/africa/topics/bacteria-406/articlesBacteria – The Conversation2024-03-29T08:28:44Ztag:theconversation.com,2011:article/2263692024-03-29T08:28:44Z2024-03-29T08:28:44ZHow to make sure your leftovers are safe to eat<figure><img src="https://images.theconversation.com/files/584372/original/file-20240326-20-oixbu7.jpg?ixlib=rb-1.1.0&rect=15%2C7%2C5144%2C3435&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Leftovers should only be stored in the fridge for a maximum of two days.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/handsome-man-putting-lunchbox-fridge-taking-2399269457">Halfpoint/ Shutterstock</a></span></figcaption></figure><p>Eating leftovers can be a great way to save money, diversify your cooking repertoire and reduce food waste. </p>
<p>But eating leftover food can also be risky as these foods have already been exposed to bacteria in the environment. If you haven’t stored and re-heated leftovers correctly, you could be putting yourself at risk of potentially life-threatening food poisoning.</p>
<p>That doesn’t mean you should start avoiding leftovers, however. By following the the correct <a href="https://www.foodstandards.gov.scot/consumers/food-safety/at-home/storage">food safety practices</a>, you can ensure you avoid harm when eating leftovers. </p>
<h2>How quickly should leftovers be refrigerated or frozen?</h2>
<p>Bacteria exist everywhere in our world, including in kitchens – and the foods within them. The bacteria that cause food to spoil can grow rapidly with the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10325786/">right nutrients, moisture and temperatures</a>. Some double in numbers in as little as 20 minutes.</p>
<p>It’s important that any leftovers are put into the fridge or freezer as quickly as possible and within two hours maximum. This time advice is based on how quickly bacteria can grow in food at non-refrigerated temperatures, and means leftover food become less safe to eat the longer it is left at more than 5°C. You should also make sure that leftovers are covered. Clingfilm and airtight lids help prevent air from getting at the food. This is important, as most pathogens <a href="https://www.britannica.com/science/bacteria/Physical-requirements">need oxygen to grow</a>.</p>
<h2>How long are refrigerated leftovers safe to eat?</h2>
<p>Your fridge should be kept at a temperature of <a href="https://ask.usda.gov/s/article/Why-is-a-refrigerator-important-for-keeping-food-safe">between 0 and 5°C</a>, as this inhibits the growth of food poisoning bacteria on leftovers. </p>
<p>Leftovers must be eaten within two days, as any longer gives harmful bacteria more time to grow. Indeed, pathogens such as <em>Listeria</em>, which can cause flu-like symptoms, <a href="https://ask.usda.gov/s/article/Why-is-a-refrigerator-important-for-keeping-food-safe">can even grow</a> in <a href="https://pubmed.ncbi.nlm.nih.gov/3146567/">refrigerated temperatures</a> and are more likely to grow beyond two days – which is why this is the recommended time limit for storing your leftovers.</p>
<p>If you don’t think you’ll eat your leftovers within that timeframe, consider freezing them. Leftovers can be kept for <a href="https://www.foodstandards.gov.scot/consumers/food-safety/at-home/storage">up to three months</a> if frozen at -18°C.</p>
<h2>What is the safest way to re-heat your leftovers?</h2>
<p>When you reheat leftovers, you must <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742775/pdf/foods-06-00107.pdf">ensure the food is piping hot</a> all the way through. If not, don’t eat it.</p>
<p>Leftover foods should be reheated to an internal temperature of <a href="https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/leftovers-and-food-safety">at least 165°F</a> (74°C). For sauces, stews, soups and gravy, it’s best to bring them to a full boil, stirring for at least three minutes. These practices will kill most bacteria and inactivate any heat-sensitive bacterial toxins that are present. </p>
<p>If reheating leftovers in the oven, set the oven temperature to at least 325°F (163°C or gas mark 3) and bake long enough to completely heat the food through to at least 74°C. If reheating leftovers in the microwave, you should also make sure they reach an internal temperature of 74°C before eating.</p>
<figure class="align-center ">
<img alt="A woman places a bowl in the microwave to reheat." src="https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584373/original/file-20240326-22-rfg43i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Make sure leftover foods are piping hot when you reheat them.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/african-woman-reheat-food-ceramic-bowl-1884606334">TommyStockProject/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Reheating food using a slow cooker is not a good idea because if foods stay at a temperature less than 165°F for several hours, this can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5742775/pdf/foods-06-00107.pdf">permit bacterial growth</a> – increasing your risk of food poisoning.</p>
<h2>Can you reheat leftovers more than once?</h2>
<p>You really should not reheat leftovers <a href="https://webarchive.nationalarchives.gov.uk/ukgwa/20190801131631/https://www.food.gov.uk/sites/default/files/media/document/sfbb-childminders-cooking-reheating.pdf">more than once</a>. Each time a food warms and cools, it provides the right temperature and amount of time needed for any harmful bacteria to start to re-grow.</p>
<p>This then makes it harder for heat kill all the pathogens present the next time you warm up the leftovers. If you don’t think you’ll eat all your leftovers within two days, consider freezing them.</p>
<h2>Can you reheat a takeaway?</h2>
<p>Whether you can safely re-heat takeaway foods depends on how you stored it. </p>
<p>If it was stored warm in the back of your car or left at room temperature in your home for more than two hours, then the meal may be a food poisoning risk – especially if you’ve already touched or partially eaten it (which introduces bacteria to the food). </p>
<p>But if you didn’t handle the food much and refrigerated it within two hours of purchase, then the takeaway is safe to re-heat – provided the next time it’s eaten it’s first heated to a piping hot temperature of at least 74°C. It also shouldn’t be stored in the fridge for more than two days. </p>
<p>There are some takeaway foods that you should be careful about saving as leftovers. Cooked rice dishes are possibly the most risky to save. Uncooked rice may contain spores of <em><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913059/pdf/foods-10-00302.pdf">Bacillus cereus</a></em>, a bacterium that causes food poisoning. </p>
<p>While the parent bacterium is killed when rice is cooked, its spores can survive the temperature of boiling water. If rice is not refrigerated within two to three hours of cooking, the spores can grow into bacteria which in turn release the rice toxins which give rise to food poisoning symptoms such as diarrhoea, abdominal pain and vomiting. The longer contaminated cooked rice is left to stand at a non-refrigerated temperature, the more <em>Bacillus cereus</em> will be present and the more unsafe the dish becomes.</p>
<p>If cooked rice needs to be saved, it should be covered once cooked and cooled quickly (ideally within 2 hours), then stored and refrigerated for no more than 24 hours. <a href="https://www.nhs.uk/common-health-questions/food-and-diet/can-reheating-rice-cause-food-poisoning/">Cooked rice leftovers</a> should be piping hot when reheated, and should never be reheated more than once. </p>
<p>Leftovers can be safe to eat so long as you take the right precautions. But if you’re ever in doubt, or don’t think you’ll eat them within two days, storing them in the freezer will give you more flexibility than storing them in the fridge.</p><img src="https://counter.theconversation.com/content/226369/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Primrose Freestone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If leftovers aren’t saved and reheated properly, it could put you at risk of food poisoning.Primrose Freestone, Senior Lecturer in Clinical Microbiology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201902024-03-22T12:31:50Z2024-03-22T12:31:50ZThin, bacteria-coated fibers could lead to self-healing concrete that fills in its own cracks<figure><img src="https://images.theconversation.com/files/578396/original/file-20240227-26-c98ze5.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C5176%2C3437&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cracked roads and sidewalks generate big costs for cities. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/CaliforniaDroughtRain/f93eda16ae2d49ad8539aaf1ad9eb92c/photo?Query=cracked%20concrete&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=260&digitizationType=Digitized&currentItemNo=17&vs=true&vs=true">AP Photo/Marcio Jose Sanchez</a></span></figcaption></figure><p>Some say there are two types of concrete – cracked and on the brink of cracking. But what if when concrete cracked, it could heal itself? </p>
<p><a href="https://research.coe.drexel.edu/caee/aim/">We’re part of a team</a> of <a href="https://scholar.google.com/citations?user=Tn72mFcAAAAJ&hl=en">materials</a> <a href="https://scholar.google.com/citations?user=AtY08c4AAAAJ&hl=en">scientists</a> and microbiologists that has <a href="https://theconversation.com/calcium-munching-bacteria-could-be-a-secret-weapon-against-road-salt-eating-away-at-concrete-roads-and-bridges-113970">harnessed the power of bacteria</a> to create biological fibers that <a href="https://doi.org/10.1016/j.conbuildmat.2023.133765">initial results suggest</a> can heal cracks in concrete. We’re working on a technology that, if we work out the kinks and manage to bring it to the market one day, could extend the life span of concrete.</p>
<h2>Cracking concrete</h2>
<p>Picture a bridge exposed to snow, rain, temperature changes and trucks carrying heavy loads. The concrete on the bridge will gradually develop cracks from stress and wear. Over time, these cracks expand, allowing water and corrosive substances that weaken the concrete to penetrate further down. </p>
<p>At some point, local authorities have to pay for repairs, which are not only expensive but also <a href="https://artbabridgereport.org/reports/2022-ARTBA-Bridge-Report.pdf">disrupt traffic and drain public resources</a>.</p>
<p>Now, consider a medical patient recovering from a severe injury. As the patient’s cells recognize the damage, they release tiny healing agents – like microscopic repair crews. These agents target the wounded area, mending tissues and restoring the cells’ functionality. What if concrete had the same kind of <a href="https://doi.org/10.1038/nmat1934">self-healing ability</a> as human tissue? </p>
<h2>A self-healing concrete</h2>
<p><a href="https://research.coe.drexel.edu/caee/aim/people/">Our team</a> at the <a href="https://research.coe.drexel.edu/caee/aim/">Advanced Infrastructure Materials lab</a> at Drexel University was inspired by self-healing tissue in the human body. We developed an addition to concrete we <a href="https://doi.org/10.1016/j.conbuildmat.2023.133765">call BioFiber</a>.</p>
<p>BioFiber has <a href="https://doi.org/10.1016/j.conbuildmat.2023.133765">three essential functions</a>: It heals itself on its own, it stops cracks from growing wider, and it remains intact inside the concrete when there aren’t any cracks. </p>
<p>Each BioFiber has <a href="https://doi.org/10.1016/j.conbuildmat.2023.133765">three key components</a>: a tough core fiber made of a polymer called polyvinyl alcohol, a porous layer of hydrogel infused with <em><a href="https://www.sciencedirect.com/topics/immunology-and-microbiology/lysinibacillus-sphaericus">Lysinibacillus sphaericus</a></em> bacteria, and a damage-responsive outer shell. When cracks hit the BioFiber, its outer shell breaks and releases the bacteria into the crack, which starts the self-healing process.</p>
<p>The strong core fibers in BioFiber <a href="https://doi.org/10.1016/j.conbuildmat.2023.133765">bridge the cracks</a> and stop them from growing wider during the healing process.</p>
<p>Surrounding the core fiber, the hydrogel layer is made up of a mesh of polymer chains at the molecular level that attract water. Their spongelike structure can absorb and hold large volumes of water. During the production process, we add calcium to help the hydrogel solidify. </p>
<p>The hydrogel itself is made up of a <a href="https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/alginate">natural polymer found in seaweed called alginate</a>, which has special properties that allow it to trap bacteria. Alginate isn’t toxic and is even safe for biomedical applications such as <a href="https://doi.org/10.1155/2020/8886095">drug delivery</a> and <a href="https://doi.org/10.3390/md21030189">tissue engineering</a>.</p>
<p>The hydrogel <a href="https://www.ncbi.nlm.nih.gov/books/NBK556071">houses endospores</a>, which are dormant bacteria. Once the outer shell cracks and the endospores are awakened from their dormant state, they facilitate the self-healing. </p>
<h2>Activating BioFiber</h2>
<p>The endospores need water to activate. Luckily, the middle hydrogel layer absorbs water well. When the concrete cracks, and water from rain, humidity or street runoff seeps in, the spores wake up. </p>
<p>The spores ingest carbon that we specifically add into the concrete mix, as well as calcium in the concrete itself. With these materials, the bacteria facilitates a chemical reaction called microbially induced calcium carbonate precipitation, or MICCP. This reaction creates <a href="https://doi.org/10.1016/j.dibe.2024.100351">calcium carbonate crystals</a>, which build up and fill in the cracks in the concrete.</p>
<p>The crystal shape varies, from sphere to needle-shaped, and each shape is strong enough to heal the cracks. We can alter the type of crystals the bacteria produces by changing the pH level, calcium source and type of bacteria.</p>
<p>Concrete acts like a solid, tough substance because it’s a mix of cement, sand, gravel and water. We toss the BioFibers into the mix and spread them out as the concrete is mixed, ensuring they’re evenly distributed throughout the mixture.</p>
<p>Once the self-healing process ends and the bacteria dies, the activated BioFiber is done – it can’t heal anymore. But since the concrete has many BioFibers distributed throughout, another fiber can mend the next crack. At the moment, we do not know how many cracks BioFiber concrete can heal, and we’re conducing more research to figure that out. </p>
<p>To feed the bacteria, we add the amount of food it needs to stay alive and heal the cracks, depending on how many cracks we anticipate them having to fix. When the bacteria runs out of food, the process stops. The bacteria can live for roughly a couple of weeks during the healing process. </p>
<p>While BioFiber shows initial promise, it does have shortcomings, which could make manufacturing it at a larger scale challenging. The manufacturing process and materials used are specialized and not always affordable and practical. While our first tests suggest that BioFiber extends the life span of concrete, we’ll need more testing, including field trials, to verify those early results.</p>
<p>We hope to eventually commercialize and manufacture the fibers at larger production scales, while in the meantime we continue to run tests and study how to improve BioFiber’s self-healing abilities. We’d like to one day get these fibers into roads and sidewalks to potentially prevent cracking in aging concrete.</p><img src="https://counter.theconversation.com/content/220190/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mohammad Houshmand works for Drexel University. He receives funding from the National Science Foundation.</span></em></p><p class="fine-print"><em><span>Yaghoob Farnam receives funding from the National Science Foundation. In addition to his role as an associate professor at Drexel University, he is co-founder and senior technical advisor for SusMaX Inc. </span></em></p>Your skin heals from cuts and scrapes on its own − what if concrete could do that too?Mohammad Houshmand, Ph.D. Candidate in Civil Engineering, Drexel UniversityYaghoob Farnam, Assistant Professor of Civil Engineering, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202802024-03-01T00:15:33Z2024-03-01T00:15:33ZWhy and how often do I need to wash makeup brushes and sponges?<figure><img src="https://images.theconversation.com/files/576120/original/file-20240216-24-9aako6.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C4928%2C3268&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/@anniespratt?utm_content=creditCopyText&utm_medium=referral&utm_source=unsplash">Annie Spratt</a> on <a href="https://unsplash.com/photos/selective-focus-photography-of-woman-applying-blush-on-on-her-face-xOEmZX6YSu8">Annie Spratt/Unsplash</a></span></figcaption></figure><p>From the bristles of brushes to the porous surfaces of sponges, your makeup kit can harbour a host of bacteria and fungi.</p>
<p>These potentially hazardous contaminants can originate not only from the cosmetics themselves, but also from the very surface of our skin. </p>
<p>So, how can we keep things hygienic and avoid microbial growth on makeup brushes and sponges? Here’s what you need to know.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-micellar-water-and-how-does-it-work-219492">What is micellar water and how does it work?</a>
</strong>
</em>
</p>
<hr>
<h2>How do germs and fungi get in my brushes and sponges?</h2>
<p>Germs and fungi can make their way into your makeup kit in lots of ways. </p>
<p>Ever flushed a toilet with the lid open with your makeup brushes nearby? There’s a good chance <a href="https://theconversation.com/mobile-phones-are-covered-in-germs-disinfecting-them-daily-could-help-stop-diseases-spreading-135318">faecal particles</a> have landed on them. </p>
<p>Perhaps a family member or housemate has used your eyeshadow brush when you weren’t looking, and transferred some microbes across in the process. </p>
<p>Bacteria that trigger a pimple outbreak can be easily transferred from the surface of your skin to a makeup brush or sponge. </p>
<p>And tiny little mites called Demodex mites, which have been linked to certain rashes and acne, live on your skin, as well, and so may end up in your sponge or brushes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A young Asian man applies makeup at a cluttered vanity." src="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=316&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=316&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=316&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=397&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=397&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=397&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Germs and fungi can make their way into your makeup in lots of ways.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gay-queer-man-nonbinary-beauty-blogger-2361479535">Chay_Tee/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invisible-skin-mites-called-demodex-almost-certainly-live-on-your-face-but-what-about-your-mascara-195451">Invisible skin mites called Demodex almost certainly live on your face – but what about your mascara?</a>
</strong>
</em>
</p>
<hr>
<p>Bacterial contamination of <a href="https://pubmed.ncbi.nlm.nih.gov/38020232/">lip cosmetics</a>, in particular, can pose a risk of skin and eye infections (so keep that in mind if you use lip brushes). Lipsticks are frequently contaminated with bacteria such as <em>Staphylococcus aureus</em>, <em>E. coli</em>, and <em>Streptococcus pneumoniae</em>.</p>
<p>Low-quality cosmetics are more likely to have higher and more diverse microbial growth compared to <a href="https://www.sciencedirect.com/science/article/pii/S1319562X23002978?pes=vor">high-quality cosmetics</a>.</p>
<p>Brushes exposed to sensitive areas like the eyes, mouth and nose are particularly susceptible to being potential sources of infection. </p>
<p>The range of conditions caused by these microorganisms includes:</p>
<ul>
<li><p>abscesses</p></li>
<li><p>skin and soft tissue infections</p></li>
<li><p>skin lesions</p></li>
<li><p>rashes</p></li>
<li><p>and dermatitis.</p></li>
</ul>
<p>In severe cases, infections can lead to invasion of the bloodstream or deep tissues. </p>
<p>Commercially available cosmetics contain varying amounts and types of preservatives aimed at inhibiting the growth of fungi and bacteria.</p>
<p>But when you apply makeup, different cosmetics with unique formulations of preservatives can become mixed. When a preservative meant for one product mixes with others, it might not work as well because they have different water amounts or pH levels.</p>
<p>So preservatives are not foolproof. We also need to observe good hygiene practices when it comes to brushes and other cosmetics applicators. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman washes a makeup brush in a sink." src="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">You don’t need to use micellar water to clean your brushes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-washing-makeup-brush-under-water-2020030193">Pixel-Shot/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Keeping brushes clean</h2>
<p>Start with the basics: never <a href="https://www.semanticscholar.org/paper/Isolation-of-Pathogenic-Microbes-from-Beauty-Salons-Hassan-Hamad/0199635290628fe326fcd04a2b8a2422884a8240">share makeup brushes or sponges</a>. Everyone carries different microbes on their skin, so sharing brushes and sponges means you are also sharing germs and fungi.</p>
<p>If you need to share makeup, use something disposable to apply it, or make sure any shared brushes are washed and sterilised before the next person uses it.</p>
<p>Clean makeup brushes by washing with hot soapy water and rinsing thoroughly.</p>
<p>How often? Stick to a cleaning routine you can repeat with consistency (as opposed to a deep clean that is done annually). <a href="https://www.aad.org/public/everyday-care/skin-care-secrets/routine/clean-your-makeup-brushes#:%7E:text=To%20protect%20your%20skin%20and,every%207%20to%2010%20days.">Once a week</a> might be a good goal for some, while others may need to wash more regularly if they are heavy users of makeup. </p>
<p>Definitely wash straight away if someone else has used your brushes or sponges. And if you’ve had an eye infection such as conjunctivitis, ensure you clean applicators thoroughly after the infection has resolved. </p>
<p>You can use bactericidal soap, 70% ethanol or chlorhexidine solutions to wash. Just make sure you wash very thoroughly with hot water after, as some of these things can irritate your skin. (While some people online say alcohol can degrade brushes and sponges, opinion seems to be mixed; in general, most disinfectants are unlikely to cause significant corrosion.)</p>
<p>For some brushes, heating or steaming them and letting them dry may also be an effective sterilisation method once they are washed with detergent. Microwaving sponges isn’t a good idea because while the heat generated by a domestic microwave would kill microbes, it would need temperatures approaching 100°C for a decent period of time (at least several minutes). The heat could melt some parts of the sponge and hot materials could be a scalding hazard.</p>
<p>Once clean, ensure brushes and sponges are stored in a dry place away from water sources (and not near an open toilet).</p>
<p>If you’re having makeup applied professionally, brushes and applicators should be sterilised or changed from person to person. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bunch of makeup brushes are set out to dry on a towel." src="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dry brushes thoroughly after washing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/after-cleaning-makeup-brushes-finish-will-653637367">prachyaloyfar/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Should I wash them with micellar water?</h2>
<p>No. </p>
<p>Not only is this expensive, it’s unnecessary. The same benefits can be achieved with cheaper detergents or alcohol (just rinse brushes carefully afterwards).</p>
<p>Disinfection methods such as using bactericidal soap, 70% ethanol, or chlorhexidine are all very good at reducing the amount of microbes on your brushes and sponges.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-micellar-water-and-how-does-it-work-219492">What is micellar water and how does it work?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/220280/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rosalie Hocking is currently the recipient of an Australian government Future Fellowship.
</span></em></p><p class="fine-print"><em><span>Enzo Palombo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Yes, you need to wash them but no, you don’t need to use micellar water to do it.Enzo Palombo, Professor of Microbiology, Swinburne University of TechnologyRosalie Hocking, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2190722024-02-22T18:16:18Z2024-02-22T18:16:18ZExtreme environments are coded into the genomes of the organisms that live there<p>An organism’s genome is a set of DNA instructions needed for its development, function and reproduction. The genome of a present-day organism contains information from its journey on an evolutionary path that starts with the
“<a href="https://doi.org/10.1007/978-3-030-30363-1_3">first universal common ancestor</a>” of all life on Earth and culminates with that organism. </p>
<p>Encoded within itself, an organism’s genome contains information that can reveal connections to its ancestors and its relatives.</p>
<h2>Other dimensions of the genome</h2>
<p>Our research explores the hypothesis that an organism’s genome could contain other types of information, <a href="https://doi.org/10.1038/s41598-023-42518-y">beyond genealogy or taxonomy</a>. We asked: Could the genome of an organism contain information that would allow us to determine the type of environment the organism lives in?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a large black lake" src="https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574213/original/file-20240207-16-upk4fk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Extremophiles have been found in environments such as Pitch Lake in Trinidad and Tobago, the largest asphalt deposit in the world.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>As unlikely as it seems, our team of computer science and biology researchers at the University of Waterloo and Western University found that to be the case for extremophiles — organisms that live and thrive in extremely harsh conditions. These environmental conditions range from extreme heat (over 100 C) to extreme cold (below -12 C), high radiation or extremes in acidity or pressure.</p>
<h2>DNA as a language</h2>
<p>We looked at genomic DNA as a text written in a “DNA language.” A DNA strand (or DNA sequence) consists of a succession of <a href="https://www.genome.gov/genetics-glossary/Nucleotide">basic units called nucleotides</a>, strung together by a sugar-phosphate backbone. There are four such different DNA units: <a href="https://www.genome.gov/genetics-glossary/acgt">adenine, cytosine, guanine and thymine (A,C,G,T)</a>. </p>
<p>Viewed abstractly, a DNA sequence can be thought of as a line of text, written with “letters” from the “DNA alphabet.” For example, “CAT” would be the three-letter “DNA word” corresponding to the three-unit DNA sequence cytosine-adenine-thymine.</p>
<p>In the 1990s, it was discovered that by <a href="https://doi.org/10.1093/nar/18.8.2163">counting occurrences</a> of such DNA words in a short DNA sequence extracted from the genome of an organism, one could identify <a href="https://doi.org/10.1093/oxfordjournals.molbev.a026048">the species of the organism</a> and the degree of its relatedness to other organisms in the evolutionary “<a href="https://doi.org/10.1038/nmicrobiol.2016.48">tree of life</a>.”</p>
<p>The mechanism of this identification or classification of an organism based on DNA word counts is similar to the process that allows us to differentiate an English book from a French book: By taking one page from each book one notices that the English text has many occurrences of the three-letter word “the,” while the French text has many occurrences of the three-letter word “les.”</p>
<p>Note that the word-frequency profile of each book is not dependent on the particular page we chose to read and on whether we considered multiple pages, a single page or an entire chapter. Similarly, the frequency profile of DNA words in a genome is not dependent on the location and on the length of the DNA sequence that was selected to represent that genome.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="rows of lights with the letters C, A, G, T projected from them" src="https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574232/original/file-20240207-33-kdilvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A DNA strand consists of a succession of basic units: adenine, cytosine, guanine and thymine (ACGT).</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>That DNA word-frequency profiles can act as a “genomic signature” of an organism was a significant discovery and, until now, it was believed that the DNA word-frequency profile of a genome only contained evolutionary information pertaining to the species, genus, family, order, class, phylum, kingdom or domain that the organism belonged to.</p>
<p>Our team set out to ask whether the DNA word-frequency profile of a genome could reveal other kinds of information — for example, information regarding the type of extreme environment that a microbial extremophile thrives in.</p>
<h2>Environment imprints in extremophile DNA</h2>
<p>We used a dataset of 700 microbial extremophiles living in extreme temperatures (either extreme heat or cold) or extreme pH conditions (strongly acidic or alkaline). We used both <a href="https://doi.org/10.1093/bioinformatics/btz918">supervised machine learning</a> and <a href="https://doi.org/10.1093/bioinformatics/btad508">unsupervised machine learning</a> computational approaches to test our hypothesis.</p>
<p>In both types of environmental conditions, we discovered that we could clearly detect an environmental signal indicating the type of extreme environment a particular organism inhabited. </p>
<p>In the case of unsupervised machine learning, a “blind” algorithm was given a dataset of extremophile DNA sequences (and no other information about either their taxonomy or their living environment). The algorithm was then asked to group these DNA sequences in clusters, based on whatever similarities it could find among their DNA word-frequency profiles. </p>
<p>The expectation was that all the clusters discovered this way would be along taxonomic lines: bacteria grouped with bacteria, and archaea grouped with archaea. To our great surprise, this was not always the case, and some archaea and bacteria were consistently grouped together, no matter what algorithms we used. </p>
<p>The only obvious commonality that could explain their being considered similar by the multiple machine learning algorithms was that they were heat-loving extremophiles.</p>
<h2>A shocking discovery</h2>
<p>The <a href="https://doi.org/10.1038/s41467-023-42924-w">tree of life</a>, a conceptual framework used in biology that <a href="https://doi.org/10.1073/pnas.87.12.4576">represents geneaological relationships</a> between species, has three major limbs, called domains: <a href="https://doi.org/10.1073/pnas.74.11.5088">bacteria, archaea and eukarya</a>.</p>
<p>Eukaryotes are organisms that have a membrane-bound nucleus, and this domain includes animals, plants, fungi and the unicellular microscopic protists. In contrast, bacteria and archaea are single-cell organisms that do not have a membrane-bound nucleus containing the genome. What distinguishes bacteria from archaea is the composition of their cell walls.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a figure showing the three branches of the tree of life" src="https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=485&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=485&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=485&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=610&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=610&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576771/original/file-20240220-22-6gkrf4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=610&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A schematic tree of life with the primary domains, archaea and bacteria, shown in purple and blue, respectively and the secondary domain, Eukaryotes, in green.</span>
<span class="attribution"><a class="source" href="https://www.eurekalert.org/multimedia/1006461">(Tara Mahendrarajah)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The three domains of life are dramatically different from each other and, genetically, a bacterium is as different from an archaeon as a polar bear (eukarya) is from an <em>E. coli</em> (bacteria). </p>
<p>The expectation was therefore that the genome of a bacterium and of an archaeon would be as far apart as possible in any clustering by any genomic similarity measure. Our finding of some bacteria and archaea clustered together, apparently just because they are both adapted to extreme heat, means that the extreme temperature environment they live in caused pervasive, genome-wide, systemic shifts in their genome language. </p>
<p>This discovery is akin to finding a completely new dimension of the genome, an environmental one, existent in addition to its well-known taxonomic dimension.</p>
<h2>Genomic impact of other environments</h2>
<p>Besides being unexpected, this finding could have implications for our understanding of the evolution of life on Earth, as well as guide our thinking into what it would take to live in outer space. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an orange sphere with a tail" src="https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576775/original/file-20240220-16-7aq8tz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Pyrococcus furiosus</em>, a thermophilic archaeon that was surprisingly grouped with thermophilic bacteria.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:P_furiosus.jpg">(Michelle Kropf/Wikimedia Commons)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Indeed, our ongoing research is exploring the existence of an environmental signal in the genomic signature of radiation-resistant extremophiles, such as <a href="https://doi.org/10.1089/ast.2020.2424"><em>Deinococcus radiodurans</em></a>, which can survive radiation exposure, as well as <a href="https://doi.org/10.1101/cshperspect.a012765">cold</a>, <a href="https://doi.org/10.1128/jb.178.3.633-637.1996">dehydration</a>, <a href="https://doi.org/10.3389/fmicb.2019.00909">vacuum conditions</a> and acid, and was shown to be able to survive in <a href="https://doi.org/10.1089/ast.2020.2424">outer space for up to three years</a>.</p><img src="https://counter.theconversation.com/content/219072/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathleen A. Hill receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).</span></em></p><p class="fine-print"><em><span>Lila Kari receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC). </span></em></p>Computer analysis of the genomes of extremophiles — organisms that live in extreme environments — reveals that their living conditions are recorded in their DNA.Kathleen A. Hill, Associate Professor Biology, Western UniversityLila Kari, Professor, Computer Science, University of WaterlooLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202832024-02-22T13:42:50Z2024-02-22T13:42:50ZBacteria can develop resistance to drugs they haven’t encountered before − scientists figured this out decades ago in a classic experiment<figure><img src="https://images.theconversation.com/files/575458/original/file-20240213-24-7w1h4o.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1480&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bacteria are evolutionarily primed to outpace drug developers.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/nihgov/28881401596/in/photolist-U4kMcq-c57xDd-L19JtW-c9uWe5-dYBMYW-a5tw3L-2joPCWz-2jfgs7P-9VPmA4-fuUV2g-fvxv6D-ot5Jyg-fvacBd-vughy5-7NapMs-7N7qSL-yrSV6f-7N5dpc-Mj3KFR-7Na6i5-ysPK3x-7Na5Wq-ftHb6n-ftXtfs-ftH7Vt-7Na6P5-tCCMPo-xvLN1S-ybiGai-yqtCoy-982F9z-ftHaAP-7N3qKg-7N674D-fvxufn-fvMDps-x2Btgv-ftHapZ-7Na6sy-7NaoHs-fuUUt8-fuUQjz-fvxptp-fuUXN2-7U2mNs-7N66b2-fvaabC-xtGans">National Institute of Allergy and Infectious Diseases, National Institutes of Health/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Do bacteria mutate randomly, or do they mutate for a purpose? Researchers have been <a href="https://doi.org/10.1017/S0022172400017125">puzzling over this conundrum for over a century</a>.</p>
<p>In 1943, microbiologist Salvador Luria and physicist turned biologist Max Delbrück <a href="https://doi.org/10.1080/09332480.2010.10739800">invented an experiment</a> to argue that bacteria mutated aimlessly. Using their test, other scientists showed that bacteria could acquire resistance to antibiotics they hadn’t encountered before.</p>
<p>The <a href="https://doi.org/10.1080/09332480.2010.10739800">Luria–Delbrück experiment</a> has had a significant effect on science. The findings helped Luria and Delbruck win the <a href="https://www.nobelprize.org/prizes/medicine/1969/summary/">Nobel Prize in physiology or medicine in 1969</a>, and students today learn this experiment in <a href="https://doi.org/10.1128/jmbe.00161-23">biology classrooms</a>. I have been studying this experiment in my work as a biostatistician for <a href="https://doi.org/10.1016/S0025-5564(99)00045-0">over 20 years</a>.</p>
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<p>Decades later, this experiment offers lessons still relevant today, because it implies that bacteria can develop resistance to antibiotics that haven’t been developed yet.</p>
<h2>Slot machines and a eureka moment</h2>
<p>Imagine a test tube containing bacteria living in nutrient broth. The broth is cloudy due to the high concentration of bacteria within it. Adding a virus that infects bacteria, <a href="https://theconversation.com/viruses-are-both-the-villains-and-heroes-of-life-as-we-know-it-169131">also known as a phage</a>, into the tube kills most of the bacteria and makes the broth clear.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of bacteriophage structure." src="https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1014&fit=crop&dpr=1 600w, https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1014&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1014&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1274&fit=crop&dpr=1 754w, https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1274&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/426550/original/file-20211014-27-n6jugx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1274&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bacteriophages are viruses that specifically infect bacteria.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/flat-illustration-of-bacteriophage-royalty-free-illustration/1285360925">Kristina Dukart/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>However, keeping the test tube under conditions favorable for bacterial growth will turn the broth cloudy again over time. This indicates that the bacteria developed resistance against the phages and were able to proliferate.</p>
<p>What role did the phages play in this change?</p>
<p>Some scientists thought the phages incited the bacteria to mutate for survival. Others suggested that bacteria routinely mutate randomly, and the development of phage-resistant variants was simply <a href="https://doi.org/10.1128/jb.28.6.619-639.1934">a lucky outcome</a>. Luria and Delbrück had been working together for months to solve this conundrum, but none of their experiments had been successful. </p>
<p>On the night of Jan. 16, 1943, Luria got a hint about how to crack the mystery while watching a colleague hit the jackpot at a slot machine. The next morning, he hurried to his lab.</p>
<p>Luria’s experiment consisted of a few tubes and dishes. Each tube contained nutrient broth that would help the bacteria <em>E. coli</em> multiply, while each dish contained material coated with phages. A few bacteria were placed into each tube and given two opportunities to generate phage-resistant variants. They could either mutate in the tubes in the absence of phages, or they could mutate in the dishes in the presence of phages.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of six test tubes and and six petri dishes, a few of the dishes containing red dots" src="https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=277&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=277&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=277&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=348&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=348&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575442/original/file-20240213-28-9m0ay7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=348&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This diagram of the Luria-Delbrück experiment depicts colonies of phage-resistant variants of <em>E. coli</em> (red) developing in petri dishes.</span>
<span class="attribution"><span class="source">Qi Zheng</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The next day, Luria transferred the bacteria in each tube into a dish filled with phages. The day after that, he counted the number of resistant bacterial colonies in each dish. </p>
<p>If bacteria develop resistance against phages by interacting with them, none of the bacteria in the tubes should have mutations. On the other hand, only a few of the bacteria – say, 1 out of 10 million bacteria – should spawn resistant variants when they are transferred into a dish containing phages. Each phage-resistant variant would grow into a colony, but the remaining bacteria would die from infection.</p>
<p>If bacteria develop resistance independently of interacting with phages, some of the bacteria in the tubes will have mutations. This is because each time a bacterium divides in a tube, it has a small probability of spawning a resistant variant. If the starting generation of bacteria is the first to mutate, at least half of the bacteria will be resistant in later generations. If a bacterium in the second generation is the first to mutate, at least an eighth of the bacteria will be resistant in later generations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four tree diagrams of green and red circles, with subsequent branches from red dots turning red" src="https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575444/original/file-20240213-30-vbeqfp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mutations that confer resistance against phages (red) early on will spawn a large number of phage-resistant variants, while mutations that occur later on will spawn only a few resistant variants.</span>
<span class="attribution"><span class="source">Qi Zheng</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Like small-prize cash-outs in slot machines, late-generation mutations occur more often but give fewer resistant variants. Like jackpots, early-generation mutations occur rarely but give large numbers of variants. Early-generation mutations are rare because early on there are only a small number of bacteria available to mutate.</p>
<p>For example, in a 20-generation experiment, a mutation occurring at the 10th generation of bacteria would give 1,024 phage-resistant variants. A mutation occurring at the 17th generation would give only four phage-resistant variants. </p>
<p>The number of resistant colonies in Luria’s experiments showed a similar pattern to that of slot machine cash-outs. Most dishes contained no or small numbers of mutant colonies, but several contained a large number of mutant colonies that Luria considered jackpots. This meant that the bacteria developed resistant variants before they interacted with the phages in the dishes.</p>
<h2>An experiment’s legacy</h2>
<p>Luria sent a note to Delbrück after his experiment was completed, asking him to check his work. The two scientists then worked together to write <a href="https://doi.org/10.1093/genetics/28.6.491">a classic paper</a> describing the experimental protocol and a theoretical framework to measure bacterial mutation rates.</p>
<p>Other scientists conducted similar experiments by replacing phages <a href="https://doi.org/10.1073/pnas.31.1.16">with penicillin</a> and with <a href="https://doi.org/10.1128/am.20.5.810-814.1970">tuberculosis drugs</a>. Similarly, they found that bacteria did not need to encounter an antibiotic to acquire resistance to it.</p>
<p>Bacteria have relied on random mutations to cope with harsh, constantly changing environments <a href="https://theconversation.com/antibiotic-resistance-is-not-new-it-existed-long-before-people-used-drugs-to-kill-bacteria-115836">for millions of years</a>. Their incessant, random mutations will lead them to inevitably develop variants that are resistant to the antibiotics of the future. </p>
<p>Drug resistance is a reality of life we will have to accept and continue to fight against.</p><img src="https://counter.theconversation.com/content/220283/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Qi Zheng does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Nobel Prize-winning Luria−Delbrück experiment showed that random mutations in bacteria can allow them to develop resistance by chance.Qi Zheng, Professor of Biostatistics, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2232242024-02-21T13:04:38Z2024-02-21T13:04:38ZGut bacteria may explain why grey squirrels outcompete reds – new research<p>Across large parts of the UK, the native red squirrel has been replaced by the grey squirrel, a North American species. As well as endangering reds, grey squirrels pose a threat to our woodlands because of the damage they cause to trees. </p>
<p><a href="https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.001793">New research</a> from my colleagues and I compared the gut bacteria of red and grey squirrels. We found that differences between the two may explain their competition and red squirrel decline, as well as why grey squirrels are so destructive to woodland.</p>
<p>Grey squirrels were introduced to the UK between 1876 and 1929 and have displaced reds in most areas of the UK. Greys carry a virus called “squirrelpox”, which doesn’t affect them but leads to sickness and often death in red squirrels.</p>
<p>Grey squirrels are bigger than red squirrels and compete with them <a href="https://www.frontiersin.org/articles/10.3389/fevo.2023.1083008/full">for food and habitat</a>.
Acorns, a widespread food source, contain tannins, which are hard for red squirrels to digest. But greys can digest acorns easily, giving them an extra edge in competing for resources. </p>
<p>Grey squirrels frequently strip the bark from deciduous trees. In commercial plantations, the damage can lead to fungal infection and result in the tree producing low quality timber. The annual cost is an <a href="https://rfs.org.uk/insights-publications/rfs-reports/report-overview-the-cost-of-grey-squirrel-damage-to-woodland-in-england-and-wales/">estimated £37 million.</a> with sycamore, oak, birch and beech frequently targeted. </p>
<p>The grey squirrels select the strongest growing trees as these have bark containing the largest volume of sap. Intriguingly, grey squirrels do not select trees with the <a href="https://www.researchgate.net/publication/230344319_Bark-stripping_by_Grey_squirrels_Sciurus_carolinensis">highest sugar content</a>. This observation has led scientists to posit that the squirrels consume bark to obtain <a href="https://www.sciencedirect.com/science/article/pii/S0378112716300421?via%3Dihub">certain micro-nutrients</a>. </p>
<h2>Gut bacteria</h2>
<p>All mammals have microorganisms living in their intestines. For example, the typical human colon is host to at least <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847071/">160 bacterial species</a>, while in birds, research has found thousands of different bacterial species in <a href="https://pubmed.ncbi.nlm.nih.gov/33868800/">chicken intestines.</a></p>
<p>The bacteria break down foods and help synthesise vitamins, complementing the enzymes secreted by the body. The diversity of these microorganisms, known as the “microbiota”, can reflect the level of health and also the diet of an individual. But we don’t know enough about the microbiota living in squirrel intestines. </p>
<p>The types of microbes present vary between species, yet the extent to which they differ between grey and red squirrels is unclear. We explored this and investigated the potential for any differences to affect competition between the two squirrel species. We also examined whether gut bacteria might be playing a role in bark stripping behaviour.</p>
<p>We sampled bacterial DNA from red and grey squirrel intestinal contents and performed gene sequencing to identify the range of bacteria present in the samples. The results were analysed to compare any important differences between the two.</p>
<figure class="align-center ">
<img alt="A cute red squirrels with a large bushy tail stands on the branch of a tree." src="https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=541&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=541&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576545/original/file-20240219-20-ivfdqj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=541&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ynys Môn off the north Wales coast is one of the few places in the UK where greys have been eradicated in favour of red squirrels.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-squirrel-views-around-north-wales-2232607907">Gail Johnson/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Calcium</h2>
<p>Calcium is an important nutrient in the body and is required for healthy bones, muscles and nerves. It is especially needed by lactating animals and ones that are young and growing.</p>
<p>We found that grey squirrels may have the capacity to obtain the calcium that exists in tree bark thanks to the presence of a bacteria called “oxalobacter” in their gut. The calcium in tree bark comes in an insoluble form and is hard for an animal to digest. But oxalobacter would be able to change this into a form that could be more digestible. </p>
<p>Calcium levels <a href="https://www.sciencedirect.com/science/article/pii/S0378112716300421?via%3Dihub">increase in trees</a> as active growth resumes after winter dormancy. This happens immediately before the main squirrel bark-stripping season of May to July. Our research may therefore help to explain the destructive behaviour of grey squirrels and why red squirrels appear to strip bark much less frequently.</p>
<p>Our research also identified a significantly higher diversity of bacteria in the intestines of grey squirrels compared to red squirrels. This could hold the key to further understanding why grey squirrels outcompete red squirrels in the UK. </p>
<p>A more diverse range of bacteria being sustained in the gut means that grey squirrels potentially may be able to access a broader range of resources than red squirrels in addition to acorns.</p>
<h2>Adenovirus</h2>
<p>The grey squirrel harbours not just the squirrelpox virus, but also another potential threat – adenovirus. While this virus causes severe intestinal lesions in some red squirrels, curiously, grey squirrels never exhibit the same symptoms.</p>
<p>This discrepancy underscores the fascinating and complex potential role of gut microbiota. Research increasingly reveals their influence on everything from digestion to immune response, and even susceptibility to disease.</p>
<p>In the context of red squirrels, understanding how variations in their gut bacteria might predispose them to adenovirus becomes crucial. This is especially pertinent for captive breeding programs, where adenovirus infections pose a hurdle to successful reintroductions of red squirrels into the wild.</p>
<p>Given we only sampled red and grey squirrels from north Wales, we hope that future studies will map the gut microbiota of other European populations too. Such future research will continue to improve our knowledge of the competition between red and grey squirrels.</p><img src="https://counter.theconversation.com/content/223224/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Craig Shuttleworth does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research suggests the gut bacteria of red and grey squirrels differ significantly, potentially explaining the decline of the native red and the success of its grey counterpart.Craig Shuttleworth, Honorary Visiting Research Fellow, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230082024-02-21T03:45:57Z2024-02-21T03:45:57ZWhy do I keep getting urinary tract infections? And why are chronic UTIs so hard to treat?<figure><img src="https://images.theconversation.com/files/576612/original/file-20240219-26-qkb5eg.jpg?ixlib=rb-1.1.0&rect=209%2C473%2C7139%2C4429&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-tired-young-tattooed-business-woman-1703410366">BAZA Productions/Shutterstock</a></span></figcaption></figure><p>Dealing with chronic urinary tract infections (UTIs) means facing more than the occasional discomfort. It’s like being on a never ending battlefield against an unseen adversary, making simple daily activities a trial.</p>
<p>UTIs happen when bacteria sneak into the urinary system, causing pain and frequent trips to the bathroom. </p>
<p>Chronic UTIs take this to the next level, coming back repeatedly or never fully going away despite treatment. <a href="https://www.ncbi.nlm.nih.gov/books/NBK557479/">Chronic UTIs</a> are typically diagnosed when a person experiences two or more infections within six months or three or more within a year.</p>
<p>They can happen to anyone, but some are more prone due to their <a href="https://www.urologyhealth.org/urology-a-z/u/urinary-tract-infections-in-adults">body’s makeup or habits</a>. Women are more likely to get UTIs than men, due to their shorter urethra and hormonal changes during menopause that can decrease the protective lining of the urinary tract. Sexually active people are also at greater risk, as bacteria can be transferred around the area.</p>
<p>Up to <a href="https://www.urologyhealth.org/urology-a-z/u/urinary-tract-infections-in-adults#Related%20Resources">60% of women</a> will have at least one UTI in their lifetime. While effective treatments exist, <a href="https://www.health.harvard.edu/bladder-and-bowel/when-urinary-tract-infections-keep-coming-back#:%7E:text=Your%20urine%20might%20be%20cloudy,they%20take%20on%20your%20life.">about 25%</a> of women face recurrent infections within six months. Around <a href="https://sciendo.com/article/10.33073/pjm-2019-048?tab=article">20–30%</a> of UTIs don’t respond to standard antibiotic. The challenge of chronic UTIs lies in bacteria’s ability to shield themselves against treatments.</p>
<h2>Why are chronic UTIs so hard to treat?</h2>
<p>Once thought of as straightforward infections cured by antibiotics, we now know chronic UTIs are complex. The cunning nature of the bacteria responsible for the condition allows them to hide in bladder walls, out of antibiotics’ reach. </p>
<p>The bacteria form biofilms, a kind of protective barrier that makes them nearly impervious to standard antibiotic treatments. </p>
<p>This ability to evade treatment has led to a troubling <a href="https://theconversation.com/rising-antibiotic-resistance-in-utis-could-cost-australia-1-6-billion-a-year-by-2030-heres-how-to-curb-it-149543">increase in antibiotic resistance</a>, a global health concern that renders some of the conventional treatments ineffective.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Underpants hanging on a clothesline" src="https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some antibiotics no longer work against UTIs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/womens-underwear-hangs-on-clothesline-687500683">Michael Ebardt/Shutterstock</a></span>
</figcaption>
</figure>
<p>Antibiotics need to be advanced to keep up with evolving bacteria, in a similar way to the flu vaccine, which is updated annually to combat the latest strains of the flu virus. If we used the same flu vaccine year after year, its effectiveness would wane, just as overused antibiotics lose their power against bacteria that have adapted. </p>
<p>But fighting bacteria that resist antibiotics is much tougher than updating the flu vaccine. Bacteria change in ways that are harder to predict, making it more challenging to create new, effective antibiotics. It’s like a never-ending game where the bacteria are always one step ahead.</p>
<p>Treating chronic UTIs still relies heavily on antibiotics, but doctors are getting crafty, changing up medications or prescribing low doses over a longer time to outwit the bacteria. </p>
<p>Doctors are also placing a greater emphasis on thorough diagnostics to accurately identify chronic UTIs from the outset. By asking detailed questions about the duration and frequency of symptoms, health-care providers can better distinguish between isolated UTI episodes and chronic conditions. </p>
<p>The approach to initial treatment can significantly influence the likelihood of a UTI becoming chronic. Early, targeted therapy, based on the specific bacteria causing the infection and its antibiotic sensitivity, may reduce the risk of recurrence. </p>
<p>For post-menopausal women, <a href="https://link.springer.com/article/10.1007/s00192-020-04397-z">estrogen therapy</a> has shown promise in reducing the risk of recurrent UTIs. After menopause, the decrease in estrogen levels can lead to changes in the urinary tract that makes it more susceptible to infections. This treatment restores the balance of the vaginal and urinary tract environments, making it less likely for UTIs to occur.</p>
<p>Lifestyle changes, such as <a href="https://journals.lww.com/co-nephrolhypertens/FullText/2013/05001/Impact_of_fluid_intake_in_the_prevention_of.1.aspx">drinking more water</a> and practising good hygiene like washing hands with soap after going to the toilet and the recommended front-to-back wiping for women, also play a big role. </p>
<p>Some swear by cranberry juice or supplements, though researchers are still figuring out <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD001322.pub2/full">how effective these remedies truly are</a>.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/cranberry-juice-can-prevent-recurrent-utis-but-only-for-some-people-203926">Cranberry juice can prevent recurrent UTIs, but only for some people</a>
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<h2>What treatments might we see in the future?</h2>
<p>Scientists are currently working on new treatments for chronic UTIs. One promising avenue is the development of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10052183/pdf/pathogens-12-00359.pdf">vaccines</a> aimed at preventing UTIs altogether, much like flu shots prepare our immune system to fend off the flu. </p>
<figure class="align-center ">
<img alt="Gynaecologist talks to patient" src="https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Emerging treatments could help clear chronic UTIs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gynecologist-talks-patient-during-medical-consultation-2298674535">guys_who_shoot/Shutterstock</a></span>
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<p>Another new method being looked at is called <a href="https://link.springer.com/article/10.1007/s12223-019-00750-y">phage therapy</a>. It uses special viruses called bacteriophages that go after and kill only the bad bacteria causing UTIs, while leaving the good bacteria in our body alone. This way, it doesn’t make the bacteria resistant to treatment, which is a big plus. </p>
<p>Researchers are also exploring the potential of <a href="https://www.mdpi.com/2079-6382/12/1/167">probiotics</a>. Probiotics introduce beneficial bacteria into the urinary tract to out-compete harmful pathogens. These good bacteria work by occupying space and resources in the urinary tract, making it harder for harmful pathogens to establish themselves. </p>
<p>Probiotics can also produce substances that inhibit the growth of harmful bacteria and enhance the body’s immune response.</p>
<p>Chronic UTIs represent a stubborn challenge, but with a mix of current treatments and promising research, we’re getting closer to a day when chronic UTIs are a thing of the past.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/phage-therapy-could-treat-some-drug-resistant-superbug-infections-but-comes-with-unique-challenges-207025">'Phage therapy' could treat some drug-resistant superbug infections, but comes with unique challenges</a>
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<img src="https://counter.theconversation.com/content/223008/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Iris Lim does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Chronic UTIs come back repeatedly or never fully go away despite treatment.Iris Lim, Assistant Professor, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2209352024-02-15T13:34:14Z2024-02-15T13:34:14ZBacteria in your gut can improve your mood − new research in mice tries to zero in on the crucial strains<figure><img src="https://images.theconversation.com/files/569636/original/file-20240116-23-4k79iu.png?ixlib=rb-1.1.0&rect=0%2C0%2C3295%2C2549&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The difference between one mouse's fear and another mouse's calm might be in their gut bacteria.</span> <span class="attribution"><span class="source">Katriel Cho</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><a href="https://ods.od.nih.gov/factsheets/Probiotics-Consumer/">Probiotics</a> have been getting a lot of attention recently. These bacteria, which you can consume from fermented foods, yogurt or even pills, are linked to a number of <a href="https://my.clevelandclinic.org/health/treatments/14598-probiotics">health and wellness benefits</a>, including reducing gastrointestinal distress, urinary tract infections and eczema. But can they improve your mood, too?</p>
<p>Behavior and mental health are complicated. But the short answer, according to my team’s <a href="https://doi.org/10.1016/j.bbi.2023.11.001">recently published research</a>, is likely yes.</p>
<p>The beneficial bacteria in probiotics become part of a community of other microscopic organisms living in your digestive system called the <a href="https://www.niehs.nih.gov/health/topics/science/microbiome">gut microbiome</a>. Your gut microbiome contains trillions of a diverse range of bacteria, fungi and viruses. </p>
<p><a href="https://doi.org/10.3389/fmicb.2020.02029">Hundreds of species of bacteria</a> are native to the intestinal tract. Each species can be broken down into hundreds of strains that can also be dramatically different from each other in their metabolism, byproducts and environmental preferences.</p>
<p>This bacterial diversity is why not all probiotics are built the same. Many research groups have shown that specific strains of <em>Lactobacillus</em> have <a href="https://doi.org/10.3390/nu15143258">mood-enhancing effects</a>. </p>
<p>But these effects seem to happen only with the right mix of bacteria in the right conditions. For example, a probiotic that can reduce symptoms of stress in someone who is worried about their calculus final may not work in someone with symptoms of post-traumatic stress disorder.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Yogurt parfair on a tablecloth" src="https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=465&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=465&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=465&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=584&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=584&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575084/original/file-20240212-16-hxn0sy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=584&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The probiotics in your yogurt may play a role in boosting mood.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/shallow-focus-photo-of-clear-drinking-glass-GbCEo-Nwyj4">Tanaphong Toochinda/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>Studying mood in mice</h2>
<p>In my work <a href="https://scholar.google.com/citations?user=X8XcETAAAAAJ&hl=en">as a neuroscientist</a>, I study how the gut influences the brain. My team and I recently <a href="https://doi.org/10.1016/j.bbi.2023.11.001">conducted experiments</a> in mice that support the idea that gut microbiota play a role in regulating stress.</p>
<p>So how do you measure the mood of mice? </p>
<p>First, we needed to understand how stressed mice behave. So we placed them under <a href="https://doi.org/10.1016/j.bbi.2023.11.001">short periods of stress</a>: They are restrained for two hours each day, given enough room to move around but not enough to groom or stand up. We envision this as the same type of stress people experience when they’re confined to a car or cubical for hours at a time. </p>
<p>Stressed mice soon exhibited depression- and anxiety-like behaviors, which we measured by monitoring how much time they spent hiding when placed in a new environment or how quickly they try to right themselves when flipped upside down.</p>
<p>While it isn’t surprising that stressed mice hide longer and are slower to right themselves, the power of their poop to change their behavior was. </p>
<p>To see if stressed behavior could be transferred through the microbiome, we used another group of mice that were entirely clean. These mice were free from any bacteria, fungi or viruses and lived in a rubber bubble. They essentially had no microbiome at all.</p>
<p>We exposed them to poop from either stressed mice or normal mice by sprinkling soiled bedding in their enclosures. Microbes from the donor mice started to populate the gut microbiomes of the clean mice.</p>
<p>Within a few weeks, the clean mice exposed to poop from stressed mice started to develop stress- and anxiety-like behavior, even though nothing else had changed. Meanwhile, clean mice exposed to poop from normal mice had no differences in their behavior. This finding suggests that the microbes in poop changed the mice’s behavior.</p>
<h2>Which bacteria affect mood?</h2>
<p>The results of our experiments led us back to our original question: Which bacteria can change your mood? </p>
<p>We started by comparing the microbes in the poop of stressed and normal mice. In our analysis, we found that a group of bacteria called <em>Lactobacillus</em> was greatly reduced in the stressed mice. Research has linked this group of bacteria to <a href="https://doi.org/10.1016/j.bbih.2020.100169">stress reduction</a> before. However, <em>Lactobacillus</em> contains over 170 different species and even more strains. </p>
<p>Currently, the probiotic supplements available to patients are <a href="https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know">unregulated and often untested</a>. In order to reliably get the most effective strains to patients, they need to be properly tested. So we had to come up with a way to test how different strains affect anxious behavior. </p>
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<a href="https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of rod-shaped Lactobacillus stained blue" src="https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574702/original/file-20240209-28-2yorsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"><em>Lactobacillus</em> are a diverse range of bacteria that can provide potential health benefits in people.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Lactobacillus_paracasei.jpg">Dr. Horst Neve/Max Rubner-Institut via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Instead of tackling this colossal task alone, we created a method that other microbiome scientists can also use to look at this group of bacteria as systematically as possible. </p>
<p>To recreate the same experimental conditions for each species of microbe, we created a group of mice with only six species of bacteria in their microbiome, the <a href="https://doi.org/10.1093/ilar/ilv012">bare minimum needed</a> for normal and healthy development, which did not include <em>Lactobacillus</em>. This way, we could add individual strains of <em>Lactobacillus</em> back into the mice’s gut microbiome and observe the effects of each strain on their behavior and biology. </p>
<p>We’ve <a href="https://doi.org/10.1016/j.bbi.2023.11.001">tested two strains</a> so far: <em>Lactobacillus intestinalis</em> ASF360 and <em>Lactobacillus murinus</em> ASF361. Mice with these two strains of <em>Lactobacillus</em> are more resilient to stress and have quieted neural pathways associated with fear.</p>
<h2>What’s next?</h2>
<p>Our study on how different strains of <em>Lactobacillus</em> affect mood is just the beginning. We hope that our research will open avenues for other scientists to test different probiotics. </p>
<p>While researchers are <a href="https://doi.org/10.1016/j.neubiorev.2019.03.023">reaching a consensus</a> that the bacteria in your digestive tract can influence your mood, and vice versa, there is still a lot of testing to be done in both animals and in people.</p>
<p>Our team is starting to develop ways to systematically test which bacteria may provide the best health outcomes in people and which probiotics are the most effective. In the meantime, give the <em>Lactobacillus</em> in your gut some love through a healthy, probiotics-rich diet.</p><img src="https://counter.theconversation.com/content/220935/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea Merchak has received funding from the National Institutes of Health (T32 NS115657, F31 AI174782).</span></em></p>The organisms living in your gut microbiome can influence your mental and physical health. Researchers have developed a way to better test for those biological effects.Andrea Merchak, Postdoctoral Associate in Neuroscience, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2153112024-02-09T16:50:23Z2024-02-09T16:50:23ZYour unique smell can provide clues about how healthy you are<figure><img src="https://images.theconversation.com/files/574043/original/file-20240207-19-o4ehc8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5291%2C3516&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-calm-teen-girl-enjoying-good-1325627765">fizkes/Shutterstock</a></span></figcaption></figure><p>Hundreds of chemicals stream from our bodies into the air every second. These chemicals release into the air easily as they have high vapour pressures, meaning they boil and turn into gases at room temperature. They give clues about who we are, and how healthy we are. </p>
<p>Since ancient Greek times, we’ve known that we smell differently when we are unwell. While we rely on blood analysis today, ancient Greek physicians used smell to diagnose maladies. If they took a whiff of your breath and described it as <em>fetor hepaticus</em> (meaning bad liver), it meant you could be headed for liver failure.</p>
<p>If a person’s whiff was sweet or fruity, physicians thought this meant that sugars in the digestive system were not being broken down, and that person had probably diabetes. Science has since shown the ancient Greeks were right – liver failure and <a href="https://tisserandinstitute.org/human-volatilome/">diabetes</a> and many <a href="https://link.springer.com/article/10.1007/s00216-023-04986-z">other diseases</a> including infectious diseases give your breath a distinctive smell.</p>
<p>In 1971, <a href="https://www.nobelprize.org/prizes/peace/1962/pauling/facts/">Nobel Laureate chemist Linus Pauling</a> <a href="https://edu.rsc.org/feature/breath-analysis/2020106.article#:%7E:text=The%20'modern%20era'%20of%20breath,in%20an%20average%20breath%20sample.">counted 250 different</a> gaseous chemicals in breath. These gaseous chemicals are called volatile organic compounds or VOCs. </p>
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<p>Since Pauling’s discovery, other scientists have <a href="https://link.springer.com/article/10.1007/s40291-023-00640-7">discovered hundreds more VOCs</a> in our breath. We have learned that many of these VOCs have distinctive odours, but some have no odour that our noses can perceive. </p>
<p>Scientists believe that whether a VOC <a href="https://tisserandinstitute.org/human-volatilome/">has an odour</a> that our noses can detect or not, they can reveal information about how healthy someone is.</p>
<p>A Scottish man’s Parkinson’s disease onset was <a href="https://www.bbc.co.uk/news/uk-scotland-47627179">identified by his wife</a>, retired nurse Joy Milner, after she was convinced the way he smelled had changed, years before he was diagnosed in 2005. This discovery has <a href="https://www.manchester.ac.uk/discover/news/smell-of-skin-could-lead-to-early-diagnosis-for-parkinsons/">led to research programmes</a> involving Joy Milner to identify <a href="https://www.scientificamerican.com/article/a-supersmeller-can-detect-the-scent-of-parkinsons-leading-to-an-experimental-test-for-the-illness/">the precise smell</a> of this disease. </p>
<p>Dogs can <a href="https://www.nature.com/articles/d41586-022-01629-8">sniff out more diseases</a> than humans because of their more <a href="https://www.understandinganimalresearch.org.uk/news/the-science-of-sniffs-disease-smelling-dogs%20-%20I%20think%20the%20previous%20nature%20link%20has%20more%20credibility%20for%20here%20also">sophisticated olfactory talents</a>. But technological techniques, like <a href="https://www.britannica.com/science/mass-spectrometry">analytical tool mass spectrometry</a>, picks up even more subtle changes in VOC profiles that are being linked to <a href="https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(20)30100-6/fulltext">gut</a>, <a href="https://www-sciencedirect-com.dcu.idm.oclc.org/science/article/pii/S0165993618305168">skin</a> and <a href="https://err.ersjournals.com/content/28/152/190011">respiratory</a> diseases as well as neurological diseases like Parkinson’s. Researchers believe that one day some diseases will be diagnosed simply by breathing into a device. </p>
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<h2>Where do VOCs come from?</h2>
<p>Breath is not the only source of VOCs in the body. They are also emitted from skin, urine and faeces. </p>
<p>VOCs from skin are the result of millions of skin glands removing metabolic waste from the body, as well as waste generated by bacteria and other microbes that live on our skin. Sweating produces extra nutrients for these bacteria to metabolise which can result in particularly odorous VOCs. Odour from sweat only makes up a fraction of the scents from VOCs though.</p>
<p><a href="https://www.nature.com/articles/nrmicro.2017.157">Our skin</a> and also our gut microbiomes are made up from a delicate balance of these microbes. Scientists think <a href="https://journals.lww.com/co-gastroenterology/abstract/2015/01000/the_gut_microbiome_in_health_and_in_disease.12.aspx">they influence our health</a>, but we don’t yet understand a lot about how this relationship works. </p>
<p>Unlike the gut, the skin is relatively easy to study – you can collect skin samples from living humans without having to go deep into the body. <a href="https://www-sciencedirect-com.dcu.idm.oclc.org/science/article/pii/S1471492221002087">Scientists think</a> skin VOCs can offer insights into how the microbiome’s bacteria and the human body work together to maintain our health and protect us from disease.</p>
<p>In my team’s laboratory, <a href="https://iopscience.iop.org/article/10.1088/1752-7163/abf20a">we are investigating</a> whether the skin VOC signature can reveal different attributes of the person it belongs to. These signals in skin VOC signatures are probably how dogs distinguish between people by smell. </p>
<p>We are at a relatively early stage in this research area but we have shown that you can tell males from females based on how acidic the VOCs from skin are. We use mass spectrometry to see this as the average human nose is not sophisticated enough to detect these VOCs. </p>
<p>We can also predict a person’s age with reasonable accuracy to within a few years from their skin VOC profile. This is not surprising considering that oxidative stress in our bodies increases as we age.</p>
<p><a href="https://www.metabolismjournal.com/article/S0026-0495(00)80077-3/pdf">Oxidative stress</a> happens when your antioxidant levels are low and causes irreversible damage to our cells and organs. <a href="https://pubs.acs.org/doi/10.1021/jasms.3c00315">Our recent research</a> found by-products of this oxidative damage in skin VOC profiles. </p>
<p>Not only are these VOCs responsible for personal scent – they are used by plants, insects and animals as a communication channel. Plants are in a <a href="https://www.nature.com/articles/s41598-017-10975-x">constant VOC dialogue</a> with other organisms including pollinators, herbivores, other plants and their natural enemies such as harmful bacteria and insects. VOCs used for this back and forth dialogue are known as pheromones. </p>
<h2>What has science shown about love pheromones?</h2>
<p>In the animal kingdom, there is good evidence VOCs can act as aphrodisiacs. Mice for example have microbes which contribute to a particularly <a href="https://www.sciencedirect.com/science/article/pii/S0960982212012687">smelly compound called trimethylamine</a>, which allows mice to verify the species of a potential mate. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0093691X21003083">Pigs</a> and <a href="https://www.nature.com/articles/4381097a">elephants</a> have sex pheromones too. </p>
<p>It is possible that humans also produce VOCs for attracting the perfect mate. Scientists have yet to fully decode skin – or other VOCs that are released from our bodies. But evidence for human love pheromones so far is <a href="https://www.science.org/content/article/do-human-pheromones-actually-exist">controversial at best</a>. <a href="https://www.newscientist.com/article/dn3835-colour-vision-ended-human-pheromone-use/">One theory suggests</a> that they were lost about 23 million years ago when primates developed full colour vision and started relying on their enhanced vision to choose a mate.</p>
<p>However, we believe that whether human pheromones exist or not, skin VOCs can reveal who and how we are, in terms of things like ageing, nutrition and fitness, fertility and even stress levels. This signature probably contains markers we can use to monitor our health and diagnose disease.</p><img src="https://counter.theconversation.com/content/215311/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aoife Morrin receives funding from Science Foundation Ireland.</span></em></p>The science of smell is an exciting area of research.Aoife Morrin, Associate Professor of Analytical Chemistry, Dublin City UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221002024-02-08T21:32:00Z2024-02-08T21:32:00ZSecrets of soil-enriching pulses could transform future of sustainable agriculture<figure><img src="https://images.theconversation.com/files/574321/original/file-20240208-20-86knbn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Root nodules of legumes such as soybeans help fix nitrogen into the soil. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/development-soybean-root-1248864754">Lidiane Miotto/Shutterstock</a></span></figcaption></figure><p>From lentils to chickpeas, and even the humble baked bean, pulses are perhaps best known as an alternative, plant-based source of protein. These plants are environmental heroes: they work together with soil microbes to “fix” nitrogen from the air, enriching the soil with nutrients to allow them to thrive.</p>
<p>As their nitrogen-fixing capacity is becoming better understood, scientists are hoping to find ways to increase productivity, and eventually apply some of these effective soil-enriching characteristics to other crops such as cereals. With the ability to fix nitrogen, crops would need less nitrogen fertiliser and soil health would simultaneously improve.</p>
<p>Pulses, the edible dry seeds of legume plants, are staple foods in the diets of both people and livestock around the world. Across Europe and the US, they are <a href="https://www.cbi.eu/market-information/grains-pulses-oilseeds/dried-beans/market-potential">commonly eaten</a> as tinned beans, chickpeas and lentils, while in sub-Saharan Africa, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794592/">cowpea</a> is among the most important legumes. </p>
<p>High in protein, carbohydrates, dietary fibres, vitamins and minerals, pulses play a fundamental role in <a href="https://www.frontiersin.org/articles/10.3389/fsufs.2022.878269/full">nutritious healthy diets</a>. Both the seeds and leaves are also used as <a href="https://www.un-ilibrary.org/content/books/9789210472579">feed for livestock</a>. For smallholder farmers in developing nations, nutritious pulses are a cost-effective substitute for animal protein and make up a large proportion of typical diets.</p>
<p>In Western Kenya, Rwanda and Burundi, people eat <a href="https://cgspace.cgiar.org/handle/10568/121077">more than 30kg beans a year</a> on average, while many African countries recommend pulses as a meat alternative in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9370574/">dietary guidelines</a>. Pulses can also be stored for <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022474X14000496">extended periods</a> without affecting their nutritional content.</p>
<h2>The magic inside root nodules</h2>
<p>Some <a href="https://doi.org/10.1016/j.jplph.2022.153765">100 million years ago</a>, legumes developed the natural ability to house beneficial bacteria inside dedicated structures called root nodules. Here, bacteria convert gaseous nitrogen from the air and soil into a form that’s accessible to the plant as nutrients.</p>
<p>So, legumes need less nitrogen fertiliser than cereal and other vegetable crops. A high-performing legume can fix up to <a href="https://www.frontiersin.org/articles/10.3389/fsufs.2021.767998/full">300kg of nitrogen per hectare</a>, which would otherwise cost farmers around $1 per kg in fertiliser to meet the nutrient needs of the plant. </p>
<p>At the <a href="https://www.ensa.ac.uk/">Enabling Nutrient Symbioses in Agriculture</a> project, we are trying to understand how exactly legumes do this. We are exploring how these nitrogen-fixing root nodules evolved in only legumes in the first place. With that knowledge, we hope to find ways to increase the efficiency of nitrogen fixation inside the root nodules and maximise the growth and yield of legume crops.</p>
<figure class="align-center ">
<img alt="microscopic image of pink cells - bacteria inside root nodules close up" src="https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Under the microscope, the nitrogen-fixing bacteria inside root nodules of a bean plant can be seen.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/root-bacteria-nodules-bean-under-microscope-1114612907">ChWeiss/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Beneficial bacteria</h2>
<p>My research group is investigating how legumes can engage with beneficial bacteria and avoid disease-causing microbes. While bacteria like the rhizobia in these root nodules help plants source nutrients, other soil microbes including bacteria and fungi could cause disease and prevent plants from converting as much nitrogen. So the plant must have a defence mechanism that keeps disease-causing microbes at bay. This may also prevent it from fully engaging with beneficial bacteria. </p>
<p>Our team of researchers has identified potential factors that limit nitrogen fixation in the nodules of <em>Medicago</em>, also known as barrel medic or barrel clover. This legume is frequently used for research and not grown for consumption. By studying these limiting factors, we hope to improve the efficiency of nitrogen fixation without affecting the crop’s in-built defence mechanisms to protect it from disease.</p>
<p>Having studied this mechanism in the research legume, researchers are now studying a few relevant crop legumes such as soybean and cowpea to understand how widespread and applicable the underlying biological mechanisms are, and whether they can be harnessed to improve other pulses in the future.</p>
<p>Despite being some of the oldest domesticated crops, many legumes are much less adapted to farming and so have significant potential for further improvement through breeding and genetic engineering, making them more suitable and sustainable for modern food systems.</p>
<p>The benefits of more efficient nitrogen fixing in legumes would include greater growth and biomass and, we hope, higher protein content in the seeds or pulses. This would increase the nutritional value per crop, meaning more high-quality nutrient-rich food could be produced per hectare.</p>
<p>Higher yields would create new opportunities for small-scale and subsistence farmers to grow and benefit from legumes – such as soybean – as cash crops to improve rural livelihoods. More productive legumes could be more effective as a <a href="https://link.springer.com/article/10.1007/s41130-018-0063-z">rotation crop</a> that improves soil health, which is especially important for farmers dealing with degraded soil, such as those found across sub-Saharan Africa. </p>
<p>The more we know about this unique ability of legumes, the greater our chance of successfully developing other crops with a similar ability. Such a development, though some years away, could transform sustainable agriculture, especially in areas where access to synthetic fertiliser is already limited by cost and availability.</p>
<p>Extending nitrogen fixing to other crops has long been an ambition of crop scientists around the world and as the study of plant biology advances, the pulse of progress is quickening.</p>
<hr>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/222100/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sebastian Schornack receives funding from Bill and Melinda Gates Agricultural Innovations. He is also listed as an inventor on a patent filed by the University of Cambridge on a gene that seems to limit nitrogen fixation.</span></em></p>New technology could unlock the soil-enriching nitrogen-fixing ability of legumes…and one day apply this to other crops too.Sebastian Schornack, Senior research group leader in the Enabling Nutrient Symbioses in Agriculture (ENSA) project, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2222962024-02-05T16:13:03Z2024-02-05T16:13:03ZA new virus-like entity has just been discovered – ‘obelisks’ explained<figure><img src="https://images.theconversation.com/files/573101/original/file-20240202-31-42ohg4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8038%2C5354&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rear-view-male-doctor-taking-bodily-1510584707">Andrey_Popov/Shutterstock</a></span></figcaption></figure><p>Biological entities called obelisks have been hiding – in large numbers – inside the human mouth and gut. These microscopic entities, which were recently discovered by a team at Stanford University, are circular bits of genetic material that contain one or two genes and self-organise into a rod-like shape. </p>
<p>Although the study is still in <a href="https://www.biorxiv.org/content/10.1101/2024.01.20.576352v1">preprint</a> form, meaning that it has not been peer-reviewed, it has already been extensively written about, including in two heavyweight journals: <a href="https://www.nature.com/articles/d41586-024-00266-7">Nature</a> and <a href="https://www.science.org/content/article/it-s-insane-new-viruslike-entities-found-human-gut-microbes">Science</a>.</p>
<p>Let’s delve deeper into the strange world of very tiny “lifeforms”.</p>
<p>In biology, as in physics, things can get weirder and the rules fuzzier as we move through smaller and smaller scales. </p>
<p>Viruses, being unable to replicate without the help of a host, can most generously be considered to be on the edge of what constitutes life. Yet the estimated <a href="https://www.nationalgeographic.com/science/article/factors-allow-viruses-infect-humans-coronavirus">10 nonillion (one followed by 31 zeroes) individual viruses</a> on the planet can be found in every conceivable habitat and, through infecting and manipulating their hosts, have probably affected the evolutionary trajectories of all life. </p>
<p>Peering even further down into the world of minuscule biological entities, are the viroids – tiny scraps of genetic material (DNA-like molecules known as RNA) that cannot make proteins and, unlike viruses, don’t have a protective shell to encase their genome. </p>
<p>Viroids are examples of ribozymes: RNA molecules that may be a distant echo of the very first self-replicating genetic elements from which cellular life emerged. </p>
<p>Viroids can self-cleave (chop up) and re-ligate (stick back together) their genome as part of the replication cycle. And, despite their simplicity, they can cause serious disease in <a href="https://pubmed.ncbi.nlm.nih.gov/33801996/">flowering plants</a>.</p>
<h2>Between a virus and a viroid – perhaps</h2>
<p>The new <a href="https://www.biorxiv.org/content/10.1101/2024.01.20.576352v1.full">preprint</a> describes “viroid-like colonists of human microbiomes”. If “viroid-like” sounds non-committal, that is entirely deliberate. The newly discovered biological entity falls somewhere between viruses and viroids. </p>
<p>In fact, the name obelisks was proposed not only because of their shape, but also to provide wiggle room in case they turn out to be more like RNA plasmids (a different type of genetic element that resides inside bacteria) than either viruses or viroids.</p>
<p>Like viroids, obelisks have a circular single-stranded RNA genome and no protein coat but, like viruses, their genomes contain genes that are predicted to code for proteins. </p>
<p>All obelisks so far described encode a single major protein known as obulin, and many encode a second, smaller obulin. </p>
<p>Obulins bear no evolutionary resemblance, or “homology”, to any other protein found, and there are few clues as to their function. </p>
<p>By analysing existing datasets taken from the gut and mouth of humans as well as other diverse sources, the Stanford team found almost 30,000 distinct obelisk types. </p>
<p>These obelisk genomes have been previously overlooked because they are so dissimilar to anything described previously. The Stanford team found them using a clever bespoke method for searching databases for single-stranded circular RNA molecules to fish out any viroid-like elements. </p>
<p>It is clear from their results that obelisks are not rare. The researchers found them in datasets spanning the globe and in diverse niches. </p>
<p>These elements were detected in around 7% of microbiome datasets from the human gut and 50% of datasets from the mouth. However, whether these datasets provide a true representation of the prevalence and distribution of obelisks is unclear. </p>
<p>Different obelisk types were found in different body sites and in different donors. Long-term data revealed that people can harbour a single obelisk type for around a year. </p>
<p>Obelisks probably rely on microbial host cells to replicate, including those that live inside humans to replicate. Bacteria or fungi are likely hosts, but it is not known which exact species harbour these elements. </p>
<p>However, the researchers provide a critical lead through the analysis by providing strong evidence that a common bacterial component of dental plaque, <em>Streptococcus sanguinis</em>, plays host to a specific obelisk type.</p>
<figure class="align-center ">
<img alt="Illustration of the human gut full of microbes" src="https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573105/original/file-20240202-29-62uqwp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We might have to re-think the gut microbiome.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendered-medical-illustration-microbiome-small-2221001821">SciePro/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Friend or foe?</h2>
<p>As <em>S sanguinis</em> is easy to grow and experiment on in the laboratory, this will provide a valuable model for understanding the fundamentals of obelisk biology. </p>
<p>This is critical, as nothing is known about the broader evolutionary and ecological significance of obelisks. They may be parasitic and harm host cells, or they may be beneficial. </p>
<p>Hosts may have evolved elaborate defence mechanisms against obelisks, or else actively recruit them to gain some unsuspected advantage. If obelisks change or upset the human microbiome, this may in turn have implications for human health – they may even have therapeutic potential. </p>
<p>Alternatively, obelisks may cause neither harm nor benefit to their microbial host, or to humans. Instead, they may simply exist as stealthy evolutionary passengers, silently and endlessly replicating, like the original “selfish gene”.</p><img src="https://counter.theconversation.com/content/222296/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ed Feil does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Your mouth and your gut is full of them. But we don’t know if they’re friend or foe.Ed Feil, Professor of Microbial Evolution at The Milner Centre for Evolution, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2208502024-01-31T19:07:41Z2024-01-31T19:07:41ZHow the weird and wonderful microbes in wastewater can make our cities more sustainable<figure><img src="https://images.theconversation.com/files/571375/original/file-20240125-23-39o9n9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4638%2C3086&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sludge-digestion-installation-on-waste-water-89462866">hans engbers/Shutterstock</a></span></figcaption></figure><p>COVID-19 showed us how useful <a href="https://theconversation.com/wastewater-monitoring-took-off-during-the-covid-19-pandemic-and-heres-how-it-could-help-head-off-future-outbreaks-180775">monitoring wastewater</a> can be. But the genetic material in our wastewater, namely DNA and RNA, is a treasure trove of other useful information. It reveals the presence of thousands of different types of weird and wonderful wastewater microbes. </p>
<p>The diversity of these microbes can “talk” to us and tell us how to get more renewable energy out of our wastes. If only we could listen to them. Soon we can. </p>
<p>How will that work? It all starts with our poo. These types of microbes have been used <a href="https://extension.psu.edu/a-short-history-of-anaerobic-digestion">since the 19th century</a> to treat and reduce the ever-increasing volumes of sewage sludge arriving at our wastewater treatment plants, especially in urban areas. <a href="https://unhabitat.org/wcr/">Two-thirds of the world’s people</a> are expected to live in urban areas by 2050, hence sewage treatment <a href="https://www.nature.com/articles/s44284-023-00021-5">will be in high demand</a>. </p>
<p>Yet most people today have little idea how vital microbes are for sustainable growth of cities. We need them to treat our waste.</p>
<p>We also need sources of renewable energy. Thanks to naturally occurring microbes, our water utilities can produce renewable biogas from human waste. By reducing our reliance on fossil fuels, their <a href="https://www.iea.org/reports/outlook-for-biogas-and-biomethane-prospects-for-organic-growth/an-introduction-to-biogas-and-biomethane">poo biogas</a> can help to mitigate climate change.</p>
<p>So we need to learn more about these microbes to ensure they are doing the best possible job of processing our waste. One way of doing that is by monitoring DNA in human waste sludge.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1119277007571841024"}"></div></p>
<h2>A living sludge mass</h2>
<p>First of all, this promising waste-to-energy technology, which fully relies on microbes, is called <a href="https://www.epa.gov/agstar/how-does-anaerobic-digestion-work">anaerobic digestion</a>. </p>
<p>Operating anaerobic digesters is expensive. It requires intense monitoring strategies and frequent interventions. That is because microbes can be unpredictable. </p>
<p>On the face of it, the process is really simple. Wastewater sludge is pumped into large vessels without oxygen, where microbes are left alone for a few days to practically eat the sludge and breathe out biogas. Sludge goes in, treated sludge plus gas goes out. </p>
<p>The process reduces overall sludge mass and the number of pathogens. This ultimately makes it a safer material, while also generating renewable energy. Brilliant, right? </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QdprryhhFbI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Using anaerobic digesters to treat human waste has multiple benefits, but depends on keeping a community of microbes healthy.</span></figcaption>
</figure>
<p>But there is a catch. This process is only effective if these living, breathing treatment vessels behave. Unfortunately, sometimes they get out of control without warning, making them difficult to manage. </p>
<p>These sludge microbes are similar to those in our gut. Once we know this, we might intuitively understand how sensitive they can be, given our experience of <a href="https://www.bmj.com/content/361/bmj.k2179.full">gastrointestinal disorders linked to our gut microbes</a>. </p>
<p>So microbial happiness is not only important for our own health, it is crucial for the health of the large digester vessels managed by wastewater treatment plants. To make it cheaper to run these facilities, we urgently need to learn more about life in our sludge.</p>
<figure class="align-center ">
<img alt="Sludge pours into a large open tank at a waste treatment plant" src="https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571376/original/file-20240125-19-vgrp27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The huge amounts of human waste we create support an extraordinarily rich variety of microbial life.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/part-sewage-treatment-plant-scene-230751835">Geermy/Shutterstock</a></span>
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</figure>
<h2>DNA, a window on an invisible world</h2>
<p>At the <a href="https://www.transformingbiosolids.org.au">ARC Biosolids Training Centre</a> we want to make anaerobic digestion easier for water utilities by developing routine DNA-based monitoring tools. Essentially, we are looking for a way to predict the process to manage it better. </p>
<p>DNA tells the story of thousands of different types of microbes that work together to treat our sludge. To optimise the wastewater treatment process we need to identify them, the troublemakers and the do-gooders. </p>
<p>But sludge life is complex. Before it can tell us its story, we require empirical studies. We have to be able to relate microbial DNA to the process. </p>
<p>To show how that works we produced a <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2022.1079136/full">review</a> of the role of microbes for monitoring anaerobic digestion. This includes some of the diversity metrics that ecologists use to assess the health of the whole system based on the composition of microbes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Compound microscope images of microbes in waste sludge" src="https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572320/original/file-20240131-23-dw2h6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Compound microscope images of just a few of the thousands of different types of microbes in wastewater sludge.</span>
<span class="attribution"><span class="source">Helen Stratton and Melody Christie, Stratton Microbial Ecology Lab at Griffith University</span></span>
</figcaption>
</figure>
<h2>The weird and the wonderful</h2>
<p>The microbes that are used to treat sludge consist of a diverse range of ancient, weird, at times alien-like bacteria and <a href="https://www.britannica.com/science/archaea">archaea</a> (another form of single-celled organisms). They can metabolise materials that no other lifeform can. </p>
<p>Amazingly, some of them <a href="https://news.mit.edu/2018/mit-researchers-determine-timing-of-methanogen-evolution-0404">existed 3.5 billion years ago</a> – the Earth formed 4.5 billion years ago. There is even <a href="https://www.nature.com/articles/s41550-022-01786-w">a chance some have existed on Mars</a>. </p>
<p>And sludge life is a very active community of microbes: some are bullies, some collaborators. Through their DNA, we count them to learn how many different types of microbes there are and how often they appear. This counted diversity can then tell us if a system is healthy or not. </p>
<p>For a healthy, productive system, <a href="https://theconversation.com/diverse-gut-microbiomes-give-better-protection-against-harmful-bugs-now-we-know-why-219734">we need diversity</a> – as many different microbes as possible – to provide stability. If a particular organism somehow starts to grow faster or slower, it means something is getting out of control.</p>
<p>We can exploit that knowledge to develop risk scores for the operators of treatment facilities. And that is what we try to do. </p>
<p>We will keep working so that someday we can properly listen to our sludge-eating microbes and get more value out of our poo.</p><img src="https://counter.theconversation.com/content/220850/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian Krohn's reseach receives funding from an Australian Research Council Industrial Transformation Training Centre Grant (IC190100033). </span></em></p>Much like our gut microbes, the community of microbes used to process human waste must be healthy to do the job well. Monitoring the DNA in waste sludge can help us ensure the system stays healthy.Christian Krohn, Postoctoral Researcher, School of Science, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2215112024-01-29T14:53:48Z2024-01-29T14:53:48ZFrom mud and vinegar to 3D printing skin, the way we treat wounds still challenges humanity<p>Whether it’s the sting of a paper cut or the trauma of battle injury, wounds are woven into the tapestry of human experience. And since ancient times, we’ve fought the enemy that lurks within them – infection. </p>
<p>The constant threat of injury on the battlefield led to the search for new ways to combat wound infection. But early surgical procedures lacked the sterile instruments available today, meaning that for many years, surgery came with the added risk of post-operative <a href="https://cha.com/wp-content/uploads/2017/11/AJIC-2012-Infection-Control-Through-the-Ages.pdf">wound infection</a>, resulting in high numbers of deaths. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3601883/">Ancient practices</a>, such as using oils, mud, turpentine, or honey to treat wounds, were common around 2000BC. The Greek physician Hippocrates (460-377BC) <a href="https://www.dermatologytimes.com/view/acetic-acid-and-wound-healing">used vinegar</a> to clean wounds, followed by bandaging to keep dirt at bay.</p>
<p>While the first hospitals were <a href="https://scientificsurgery.bjs.co.uk/article/the-surgery-of-theodoric-ca-a-d-1267-translated-from-the-latin-by-eldridge-campbell-m-d-and-james-colton-m-a-volume-i-books-i-and-ii-8-38-x-5-12-in-pp-223-xi-with-coloured-front/">established</a> in Europe in the middle ages, they were dangerous and brutal places. Wound infection rates were high because of unsanitary conditions and the use of cautery, which involved pushing a burning iron into a patient’s wound until it reached the bone.</p>
<figure class="align-center ">
<img alt="A drawing of a pot containing a fire with several medical instruments poking out of it." src="https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571587/original/file-20240126-19-5nmbkg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A receptacle for burning coal to heat cautery instruments.</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/gcg933n2/images?id=jghkdnp4">Wellcome Collection</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>By the 1860s, the pioneering surgeon Joseph Lister had revolutionised wound infection treatment by introducing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895849/">carbolic-acid-soaked bandages</a>. And Robert Wood Johnson, who founded Johnson & Johnson, <a href="https://wounds-uk.com/journal-articles/sterilised-gauze-and-baby-powder-robert-wood-johnson-i-and-frederick-barnett-kilmer/">produced</a> the first sterile gauze bandages by 1890. The combination of antiseptic and sterile bandage marked a turning point in the evolution of wound treatment and infection control.</p>
<p>The discovery of penicillin by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4520913/">Alexander Fleming</a> in 1928 was also a pivotal moment in the treatment of wound infections. By the 1940s, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5369031/">penicillin</a> was being used to treat second world war soldiers who had wound infections that would have been deemed fatal in previous years. For less serious wounds, Lister’s approach of using a dressing and an antiseptic was still used.</p>
<p>Substances like <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756674/">silver</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/12914356/">iodine</a> have also been recognised for their antimicrobial properties since the 1800s. Iodine, though effective, caused pain and skin discolouration until safer and less painful formulations were developed in 1949. <a href="https://bnf.nice.org.uk/wound-management/antimicrobial-dressings/">These formulations</a> endure in modern wound dressings.</p>
<p>For everyday cuts and scrapes, a simple cleaning with water and application of antiseptic cream is usually enough. This helps to prevent the inadvertent introduction of bacteria into the wound, minimising the risk of additional pain and swelling. </p>
<p>But while most wounds nowadays heal without issue, some become become infected. Research published in 2021 showed that <a href="https://wounds-uk.com/wp-content/uploads/sites/2/2023/02/68803cd147c4d81a02b9cc56823f19a1.pdf">3.8 million</a> people were having their wounds managed by the NHS between 2017 and 2018, up 71% from between 2012 and 2013. They included surgical wounds, leg ulcers and burns. This shows how hard it can be to care for wounds that are difficult to heal and particularly susceptible to infections.</p>
<h2>Modern-day challenges</h2>
<p>One of the biggest challenges in the modern-day treatment of wound infection is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">antibiotic resistance</a>. This happens when bacteria develop the ability to defeat the drugs designed to kill them. Resistant infections can be difficult, and sometimes impossible, to treat. </p>
<p>Many bacteria have also become resistant to the antimicrobial ingredients used in wound dressings. This is the case for <a href="https://www.sciencedirect.com/science/article/pii/S0195670104005201">silver-based</a> wound dressings, which are often used to treat chronic wound infections. This type of wound characteristically <a href="https://www.nature.com/articles/s41572-022-00377-3">fails to heal</a>, and can remain an open, infected wound for many months – or even years. As well as the devastating effect on people’s quality of life, this also places a huge financial burden on the NHS.</p>
<p>The constant fight against wound infections drives extensive research for new, safe and effective treatments. While progress is being made, a crucial hurdle lies in the <a href="https://academic.oup.com/jacamr/article/3/1/dlab027/6186407">limitations</a> of laboratory testing methods. These tests, while necessary for regulatory approval, often fail to capture the nuanced realities of wounds in the human body. </p>
<p>No two people are the same and no two wounds are the same either. This can lead to situations where treatments shine in the lab but ultimately prove ineffective in real patients.</p>
<h2>Creating wound models</h2>
<p>In response to this, scientists are tackling the limitations of lab tests by creating more realistic synthetic wound models. Some are even <a href="https://pubmed.ncbi.nlm.nih.gov/30172300/">3D printing</a> human skin (using leftovers from surgical procedures), or animal skin, complete with artificial body fluids, such as pus. The aim is to create a model environment that mimics real wounds more accurately. </p>
<p>Recently, my own <a href="https://pubmed.ncbi.nlm.nih.gov/36678466/">research group</a> has made strides in developing lab models that act like real chronic wounds when treated with antimicrobial dressings. While not perfect, our models are a step in the right direction, contributing to the development of formulations with promising potential for treating wound infections in the future.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-built-a-human-skin-printer-from-lego-and-we-want-every-lab-to-use-our-blueprint-203170">We built a human-skin printer from Lego and we want every lab to use our blueprint</a>
</strong>
</em>
</p>
<hr>
<p>As we navigate the complexities of wound care, the quest for new, effective and safe treatments continues, driven by the efforts of scientists worldwide. We are working towards a future where the management of difficult-to-heal wounds and infections improves, enhancing both individual wellbeing and the efficiency of health systems.</p><img src="https://counter.theconversation.com/content/221511/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Maddocks does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Keeping wounds clean and infection free has challenged people for thousands of years.Sarah Maddocks, Lecturer in Microbiology, Cardiff Metropolitan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2160832024-01-09T00:57:38Z2024-01-09T00:57:38ZHow often should you wash your sheets and towels?<figure><img src="https://images.theconversation.com/files/558552/original/file-20231109-17-a2kns6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7536%2C5026&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/laundry-fresh-woman-smelling-towel-after-2246392501">PeopleImages.com - Yuri A/Shutterstock</a></span></figcaption></figure><p>Everyone seems to have a different opinion when it comes to how often towels and <a href="https://7news.com.au/video/lifestyle/cleaning/dr-karl-on-how-often-you-should-wash-our-sheets-bc-6320410318112">bed sheets should be washed</a>. While many people might wonder whether days or weeks is best, in one survey from the United Kingdom, <a href="https://www.bbc.com/news/newsbeat-61259074">almost half of single men</a> reported not washing their sheets for up to four months at a time. </p>
<p>It’s fairly clear that four months is too long to leave it, but what is the ideal frequency? </p>
<p>Bed linen and towels are quite different and so should be washed at different intervals. While every week or two will generally suffice for sheets, towels are best washed every few days.</p>
<p>Anyway, who doesn’t love the feeling of a fresh set of sheets or the smell of a newly laundered towel?</p>
<h2>Why you should wash towels more often</h2>
<p>When you dry yourself, you deposit thousands of <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2018.02362/full">skin cells</a> and millions of <a href="https://www.ajicjournal.org/article/S0196-6553(23)00402-9/fulltext">microbes</a> onto the towel. And because you use your towel to dry yourself after a shower or bath, your towel is regularly damp.</p>
<p>You also deposit a hefty amount of dead skin, microbes, sweat and oils <a href="https://theconversation.com/your-bed-probably-isnt-as-clean-as-you-think-a-microbiologist-explains-163513">onto your sheets</a> every night. But unless you’re a prolific night sweater, your bedding doesn’t get wet after a night’s sleep. </p>
<p>Towels are also made of a thicker material than sheets and therefore tend to stay damp for longer. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/all-the-reasons-you-might-be-having-night-sweats-and-when-to-see-a-doctor-211436">All the reasons you might be having night sweats – and when to see a doctor</a>
</strong>
</em>
</p>
<hr>
<p>So what is it about the dampness that causes a problem? Wet towels are a breeding ground for bacteria and moulds. <a href="https://www.qld.gov.au/housing/public-community-housing/public-housing-tenants/looking-after-your-home/safety/mould">Moulds</a> especially love <a href="https://www.asthmaandlung.org.uk/living-with/indoor-air-pollution/allergies">damp environments</a>. Although mould won’t necessarily be visible (you would need significant growth to be able to see it) this can lead to an unpleasant smell.</p>
<p>As well as odours, <a href="https://www.nhs.uk/common-health-questions/infections/can-clothes-and-towels-spread-germs/">exposure to these microbes</a> in your towels and sheets can cause <a href="https://aafa.org/allergies/types-of-allergies/insect-allergy/dust-mite-allergy/">asthma</a>, allergic skin irritations, or other <a href="https://wwwnc.cdc.gov/eid/article/11/4/04-1094_article">skin infections</a>.</p>
<figure class="align-center ">
<img alt="A couple changing the sheets on their bed." src="https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558551/original/file-20231109-17-6185x9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People don’t always agree on how often to change the sheets.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-couple-changing-bed-sheet-together-1051726535">Rawpixel.com/Shutterstock</a></span>
</figcaption>
</figure>
<h2>So what’s the ideal frequency?</h2>
<p>For bedding, it really depends on factors such as whether you have a bath or shower just before going to bed, or if you fall into bed after a long, sweaty day and have your shower in the morning. You will need to wash your sheets more regularly in the latter case. As a rule of thumb, once a week or every two weeks should be fine. </p>
<p>Towels should ideally be washed more regularly – perhaps every few days – while your facecloth should be cleaned after every use. Because it gets completely wet, it will be wet for a longer time, and retain more skin cells and microbes. </p>
<p>Wash your towels at a high temperature (for example, 65°C) as that will <a href="https://pubmed.ncbi.nlm.nih.gov/34465009/">kill many microbes</a>. If you are conscious of saving energy, you can use a lower temperature and add a cup of vinegar to the wash. The vinegar will kill microbes and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8231443/">prevent bad smells</a> from developing. </p>
<p>Clean your washing machine regularly and dry the fold in the rubber after every wash, as this is another place microbes like to grow. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/research-check-can-tea-towels-cause-food-poisoning-98152">Research Check: can tea towels cause food poisoning?</a>
</strong>
</em>
</p>
<hr>
<h2>Smelly towels</h2>
<p>What if you regularly wash your towels, but they still smell bad? One of the reasons for this pong could be that you’ve left them in the washing machine too long after the wash. Especially if it was a warm wash cycle, the time they’re warm and damp will allow microbes to happily grow. Under <a href="https://textbookofbacteriology.net/growth_3.html">lab conditions</a> the number of these bacteria can double every 30 minutes.</p>
<p>It’s important to hang your towel out to dry after use and not to leave towels in the washing machine after the cycle has finished. If possible, hang your towels and bedding out in the sun. That will dry them quickly and thoroughly and will foster that lovely fresh, clean cotton smell. Using a dryer is a good alternative if the weather is bad, but outdoors in the sun is always better if possible.</p>
<p>Also, even if your towel is going to be washed, don’t throw a wet towel into the laundry basket, as the damp, dirty towel will be an ideal place for microbes to breed. By the time you get to doing your washing, the towel and the other laundry around it may have acquired a bad smell. And it can be difficult to get your towels smelling fresh again. </p>
<figure class="align-center ">
<img alt="A young woman loading a washing machine." src="https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6709%2C4476&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558550/original/file-20231109-15-2gv66g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Towels should be washed more often than sheets.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-taking-laundry-out-washing-1727564893">New Africa/Shutterstock</a></span>
</figcaption>
</figure>
<h2>What about ‘self-cleaning’ sheets and towels?</h2>
<p>Some companies sell “quick-dry” towels or “self-cleaning” towels and bedding. Quick-dry towels are made from synthetic materials that are weaved in a way to allow them to dry quickly. This would help prevent the growth of microbes and the bad smells that develop when towels are damp for long periods of time.</p>
<p>But the notion of self-cleaning products is more complicated. Most of these products contain <a href="https://www.degruyter.com/document/doi/10.1515/chem-2016-0005/html">nanosilver</a> or copper, antibacterial metals that kill micro-organisms. The antibacterial compounds will stop the growth of bacteria and can be useful to limit smells and reduce the frequency with which you need to clean your sheets and towels. </p>
<p>However, they’re not going to remove dirt like oils, skin flakes and sweat. So as much as I would love the idea of sheets and towels that clean themselves, that’s not exactly what happens. </p>
<p>Also, excessive use of antimicrobials <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6636436/pdf/idr-12-1985.pdf">such as nanosilver</a> can lead to <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2021.652863/full">microbes becoming resistant</a> to them.</p><img src="https://counter.theconversation.com/content/216083/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rietie Venter received funding from various national and international funding bodies.</span></em></p>While every week or two will generally suffice for sheets, towels are best washed every few days. A microbiologist explains.Rietie Venter, Associate professor, Clinical and Health Sciences, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2205642024-01-05T14:54:09Z2024-01-05T14:54:09ZNew antibiotic zosurabalpin shows promise against drug-resistant bacteria – an expert explains how it works<figure><img src="https://images.theconversation.com/files/567989/original/file-20240105-24-a6i28q.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5120%2C2880&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Carbapenem-resistant Acinetobacter baumannii is classified as a priority 1 critical pathogen by the World Health Organization</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/medical-science-laboratory-portrait-beautiful-black-1922200124">Gorodenkoff/Shutterstock</a></span></figcaption></figure><p>Researchers have <a href="https://www.nature.com/articles/s41586-023-06799-7">identified</a> an entirely new class of antibiotic that can kill bacteria that are resistant to most current drugs. </p>
<p>Zosurabalpin is highly effective against the bacterium carbapenem-resistant <em>Acinetobacter baumannii</em> (Crab), which is <a href="https://www.who.int/news/item/27-02-2017-who-publishes-list-of-bacteria-for-which-new-antibiotics-are-urgently-needed">classified</a> as a “priority 1” pathogen by the World Health Organization due to its growing presence in hospitals.</p>
<p>Crab <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9137960/">can kill</a> up to 60% of people infected with it. It commonly causes infections of the urinary tract, respiratory tract and blood stream, potentially leading to sepsis. It is responsible for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913636/">around 20%</a> of infections in places like hospitals, care homes or other similar healthcare settings.</p>
<p>Antibiotics commonly work by crossing the cell wall that surrounds infectious bacteria to reach the vital machinery inside. Once inside the cell, antibiotics block that machinery in such a way as to either stop the bacteria from growing or to cause cell death. </p>
<p>Crab is a clinical challenge as it has a double-layered cell wall, a feature that microbiologists describe as “<a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/gram-negative-bacteria">gram negative</a>”. This means that antibiotics need to cross both layers to reach the vital machinery inside the bacteria to kill them and treat the infection. </p>
<p>An exception to this rule is penicillin-based antibiotics, where the target is in the cell wall itself. These antibiotics, known as <a href="https://www.bmj.com/content/344/bmj.e3236">carbapenems</a>, were derived from penicillin some 48 years after it was first discovered and still work in the same way. However, they have undergone clever chemical modification to prevent bacteria successfully evolving to resist them. This makes them a vital part of treating infections like those caused by <em>Acinetobacter baumannii</em>. </p>
<p>But Crab, the superbug version of this infection, has developed the ability to break down carbapenems, giving it an evolutionary upper hand, which has led to its rise to supremacy in hospitals. </p>
<h2>Zosurabalpin</h2>
<p>This new class of antibiotic, zosurabalpin, is shown to be highly effective against Crab both in the laboratory and in infected animals. Researchers tested zosurabalpin against more than 100 Crab samples from patients suffering from the infection. The research team, <a href="https://www.nature.com/articles/s41586-023-06799-7">found</a> that zosurabalpin was able to kill all of these bacterial strains. It could also kill the bacteria in the bloodstream of mice infected with Crab, preventing them from developing sepsis. </p>
<p>Crab has the ability to make a toxin called <a href="https://www.sciencedirect.com/topics/neuroscience/lipopolysaccharide">lipopolysaccharide</a> that it uses as part of its weaponry for infecting people and which it normally embeds into its outer cell wall. </p>
<p>Zosurabalpin works by blocking a molecular machine called <a href="https://www.nature.com/articles/s41586-023-06873-0">LptB2FGC</a> that transports the lipopolysaccharide toxin from the inside barrier to the outside one. This makes the toxin build up inside the bacteria, causing the Crab cells to die. Essentially, the bacteria pull the pin out of their own grenade but zosurabalpin stops them from being able to throw it. </p>
<p>This LptB2FGC mechanism is pretty unique to Crab, which has some advantages and disadvantages. The bad news is that zosurabalpin will only kill Crab infections and not those caused by other types of bacteria. This means doctors would need to accurately diagnose patients with this infection to decide if zosurabalpin would be the right drug. </p>
<p>But a major advantage is that the chance of antibiotic resistance emerging is reduced, as this resistance could only emerge from Crab and not other types of bacteria. Hopefully, this could extend the shelf life of this drug. </p>
<p>The researchers say they have already seen some mutations in the drug target, LptB2FGC. However, these only seem to reduce the effectiveness of zosurabalpin, rather than stopping it working entirely. The great news is that this is the first time an antibiotic has been reported to work in this way. It gives microbiologists a new avenue to explore ways to kill our bacterial enemies before they kill us. </p>
<figure class="align-center ">
<img alt="Close up of microscope with lab glassware." src="https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568021/original/file-20240105-25-qzeyh5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zosurabalpin is effective against the bacteria, Crab, which can kill up to 60% of people infected with it.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/microscope-lab-glassware-science-laboratory-research-530971462">totojang1977/Shutterstock</a></span>
</figcaption>
</figure>
<p>Zosurabalpin is now in phase 1 clinical trial for use in patients infected with Crab. This early testing in humans will help the company developing the drug, Roche, to work out any side effects of the drugs as well as potential toxicity. Most importantly, they need to check that the drug works just as well in humans as it did in mice, and look to see if any antibiotic resistance emerges in the trial patients. </p>
<p>It’s early days and the failure rate for new antibiotic development is high, but scientists are rising to the challenge. This discovery offers significant opportunities to the scientific field as a whole and a vital lifeline in the fight against antibiotic-resistant infections.</p><img src="https://counter.theconversation.com/content/220564/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Cox receives research funding from UKRI, charities and industry.
He is Co-Director of the Antibiotic Discovery Accelerator (ABX) Network </span></em></p>Zosurabalpin is highly effective against dangerous bacterium Crab, which can kill up to 60% of people infected with it.Jonathan Cox, Senior Lecturer in Microbiology, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183072023-12-21T11:58:11Z2023-12-21T11:58:11ZWhy IBD is so hard to treat – and how scientists are making progress<figure><img src="https://images.theconversation.com/files/564472/original/file-20231208-21-jio13j.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5455%2C3628&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">IBD can be debilitating </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/illustration-intestine-internal-organs-womens-body-1828134221">Emily frost/Shutterstock</a></span></figcaption></figure><p>Inflammatory bowel disease (IBD) is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478758/">life altering</a> chronic illness that is <a href="https://bmjopen.bmj.com/content/13/3/e065186">rising dramatically globally</a>. It is stubbornly difficult to treat, and many people find the treatments we have just don’t work for them. </p>
<p>Over the last 30 years, there has been almost a 50% increase in cases – now affecting around 5 million people. Not to be confused with irritable bowel syndrome (IBS) which is a condition that affects the digestive system, IBD is more serious. It is the term for two severe illnesses called <a href="https://www.nhs.uk/conditions/crohns-disease/">Crohn’s disease</a> and <a href="https://www.nhs.uk/conditions/ulcerative-colitis/">ulcerative colitis</a>. More women are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9958616/#:%7E:text=Male%20predominance%20in%20IBD.,%2C%202.32%3A1%20in%20CD.">diagnosed with Crohn’s disease</a> while more men are affected by ulcerative colitis. </p>
<p>People with IBD can experience a variety of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4106026/">symptoms</a>, ranging from diarrhoea and blood in the stool, to weight loss and belly aches. On paper, this may sound no worse than mild food poisoning, however, this is no normal stomach upset. </p>
<p>Experiences are often extreme; people with IBD can suffer excruciating pain and in some cases, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9963331/">require surgery</a> to remove parts of the bowel. This is done by redirecting the bowel to a hole in the abdomen, where faeces are collected in a <a href="https://www.nhs.uk/conditions/colostomy/">colostomy bag</a>. </p>
<p>However, we still don’t fully understand the cause of IBD. </p>
<h2>The impact of inflammation</h2>
<p>The main symptom of IBD is excessive and uncontrolled <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5805548/">inflammation</a> – normally a sign of the body fighting off an infection. Although inflammation is an important aspect of our immune system, in IBD it is happening when the body is not under attack. Since we don’t know what causes this over-the-top reaction, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8720971/">treatments</a> are limited to managing the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964397/">derailed immune system</a>. </p>
<figure class="align-center ">
<img alt="Man holds his abdomen." src="https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566014/original/file-20231215-17-6sqtab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Many people with IBD are still in pain after treatment.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/men-stomach-pain-causes-abdominal-include-2134025051">onstockphoto/Shutterstock</a></span>
</figcaption>
</figure>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373857/">Inflammation is controlled</a> by cell signalling. Our cells detect bacteria using receptors that attach to parts of bacteria. This activates the receptor, causing it to send a signal to proteins, and each protein sends on more signals, creating a signal cascade. This is what tells the body it’s under attack. </p>
<p>Many treatments follow the strategy of intercepting signals and preventing the signal cascade from starting. However, they are <a href="https://journals.lww.com/co-gastroenterology/abstract/2022/07000/management_of_refractory_inflammatory_bowel.6.aspx">not effective</a> for many people. </p>
<p>Scientists are trying to target a different protein network, called <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924159/">NOD2</a>, that often goes haywire in people with IBD but is not targeted by current treatments. A protein, called <a href="https://www.frontiersin.org/articles/10.3389/fphar.2021.650403/full">RIPK2</a>, seems like a promising target since it is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939834/">only found</a> in this network. Researchers from the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10485824/">European Molecular Biology Laboratory</a> are investigating its structure to help scientists design a new medication that will block the signals from this protein. </p>
<h2>Importance of the microbiome</h2>
<p>Another inspiration for new treatments comes from the bacteria residing in our guts. This community of bacteria, called the gut microbiome, has been associated with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6314516/">all sorts of health conditions</a> ranging from asthma to obesity. </p>
<p>Gut bacteria work closely with our bodies and play a vital role in digesting food and managing our <a href="https://www.nature.com/articles/s41422-020-0332-7">immune system</a>. In a healthy person, there is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143175/">fine balance</a> between gut bacteria and the immune system. Disruption of this balance can lead to disease, starting from minor discomfort to more severe, long-term conditions. </p>
<p>Scientists are trying to understand how our bodies interact with gut bacteria, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102608/">what changes</a> when people develop IBD. </p>
<p>The gut microbiome is an ecosystem. Just like a forest has animals eating different things, microbes can form a <a href="https://www.frontiersin.org/articles/10.3389/fevo.2019.00153/full">food web</a>. Some bacteria will use up one type of food, while others feed off other foods. Some rely on the waste of other bacteria after they’ve eaten. It is now believed that disruption to the gut microbiome is a characteristic of IBD and contributes to its development and progression.</p>
<p>It’s a chicken and egg situation. Is there a change in the bacteria and food web that alters our bodies? Or does something else in the body, like our immune system, change the food web, subsequently limiting which bacteria can grow? Scientists aren’t sure of the answer. </p>
<p>Instead of trying to figure out what happens first, a team at the <a href="https://www.nature.com/articles/s41467-023-42112-w">Hudson Institute of Medical Research</a> in Australia have focused on investigating which interactions in the food web are the most affected in IBD. This could help scientists to prioritise certain gut bacteria, or their food source, to restore the balance in the microbiome and improve patients’ symptoms. </p>
<p>Hopefully, this specialised targeting of the microbiome will lead to more effective and longer lasting treatments. </p>
<p>Although we have a long way to go before these ideas for treatments can become a reality, it is a step in the right direction. Targeting a new signalling pathway will hopefully control the inflammation in more patients. And studying the microbiome may reveal how we can reverse changes associated with IBD.</p>
<p>Since they are key features of IBD, these developments could allow doctors to stop the disease in the early stages and reduce complications.</p><img src="https://counter.theconversation.com/content/218307/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Falk Hildebrand receives funding from the Biotechnology and Biological Sciences Research Council (BBSRC), European Research Council, Bill & Melinda Gates Foundation and Natural Environment Research Council (NERC).</span></em></p><p class="fine-print"><em><span>Katarzyna Sidorczuk receives funding from the Biotechnology and Biological Sciences Research Council (BBSRC) and European Research Council H2020 StG.</span></em></p><p class="fine-print"><em><span>Wing Koon receives funding from the UKRI Medical Research Council for the Microbes, Microbiomes, and Bioinformatics Doctoral Training Partnership as a CASE Award in collaboration with Oxford Nanopore Technologies.</span></em></p>The current treatments for inflammatory bowel disease do not work for everyone. Tapping into new areas of biology may be the key to developing new therapies.Falk Hildebrand, Researcher in Bioinformatician, Quadram InstituteKatarzyna Sidorczuk, Research Scientist in Metagenomics, Quadram InstituteWing Koon, PhD student in Bioinformatics, Quadram InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2192842023-12-19T13:14:58Z2023-12-19T13:14:58ZHow active are the microorganisms in your yogurt? We created a new tool to study probiotic activity — and made it out of cardboard<figure><img src="https://images.theconversation.com/files/565830/original/file-20231214-19-q51cra.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4244%2C2920&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fermented foods can be a good source of probiotics. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fermented-vegetables-sauerkraut-with-carrots-and-royalty-free-image/1279140719?phrase=probiotic+food&adppopup=true">Yulia Naumenko/Moment via Getty Images</a></span></figcaption></figure><p>Humans have been fermenting food and drinks — everything from kimchi and yogurt to beer and kombucha — for <a href="https://doi.org/10.3390%2Ffoods10112861">more than 13,000 years</a>. </p>
<p>Fermentation – a natural process that uses microorganisms to create alcohols and acids from carbohydrates – can preserve food so it lasts longer, and it can enhance the quality of a food by turning some components into more easily digestible forms. </p>
<p>Some fermented foods that contain live microorganisms are <a href="https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know">called probiotics</a>, which can increase the shelf life of food and provide a range of additional benefits, like promoting a healthy <a href="https://theconversation.com/which-microbes-live-in-your-gut-a-microbiologist-tries-at-home-test-kits-to-see-what-they-reveal-about-the-microbiome-181392">gut microbiome</a> and lowering cholesterol levels.</p>
<p><a href="https://scienceweb.clemson.edu/uacl/">We are</a> <a href="https://scholar.google.com/citations?user=0kmXuxYAAAAJ&hl=en">chemists</a>, and our team wanted to figure out a way to understand which probiotics are the most active in the body. So we developed a cardboard sensor that could monitor the metabolic activity of probiotics.</p>
<h2>Probiotic health benefits</h2>
<p>As they are generally <a href="https://doi.org/10.1086/523331">considered safe</a>, probiotics are also one of the most popular dietary supplements in today’s market, accounting for more than <a href="https://finance.yahoo.com/news/global-probiotics-market-size-worth-075000774.html">US$50 billion</a> per year. </p>
<p><em>Lactobacillus</em>, <em>Bifidobacterium</em> and <em>Saccharomyces</em> are the most common probiotics. For example, food manufacturers use starter cultures of <em><a href="https://www.healthline.com/health/digestive-health/lactobacillus-bulgaricus">Lactobacillus bulgaricus</a></em> and <em><a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/streptococcus-thermophilus">Streptococcus thermophilus</a></em> to clot milk and make yogurt.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Z-DfrsyAMTw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Probiotic-packed foods can help with gut health.</span></figcaption>
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<p><a href="https://doi.org/10.1038/s41575-019-0173-3">Recent studies</a> have also found that probiotics may prevent the development of harmful bacteria in the body, lower cholesterol levels, reduce constipation, control blood pressure, enhance the production of vitamins, improve calcium absorption and boost the immune system. </p>
<p>However, probiotics can only provide health effects when the microorganisms are alive, meaning they’re metabolically active and <a href="https://www.nature.com/articles/s41575-019-0173-3/figures/1">interacting with the host’s body</a>. So, the type of probiotic, its formulation, and how it’s processed become critically important. </p>
<h2>Analyzing probiotics</h2>
<p>Probiotics grow from individual cells into colonies. Food scientists can study probiotics by counting the number of viable cells – also called colony forming units – in the food to figure out how much they might grow and how active they’ll be. They can also study how probiotics respond to <a href="https://doi.org/10.1016/j.crfs.2021.04.006">a gastric juice made in the lab</a> to simulate how probiotics act in your gut. <a href="https://www.britannica.com/science/human-digestive-system/Gastric-secretion">Gastric juice</a> is the fluid secreted in your stomach during digestion. </p>
<p>But most of these tests are slow and involve expensive instruments and skilled personnel. That’s where our cardboard sensors come in.</p>
<p>Our research team has collaborated with a research <a href="https://www.iq.usp.br/trlcp/">team from Brazil</a> to develop a simple sensor that can measure the <a href="https://doi.org/10.1002/anse.202300056">metabolic activity of probiotic foods</a>. </p>
<p>We built the sensors using standard cardboard and a process called laser scribing. We use a laser to convert a small amount of the cardboard into carbon, making it electrically conductive. We also used gold nanoparticles, which further improve the sensor’s response by decreasing the material’s resistivity.</p>
<p>Lowering the resistivity of the material is important because the sensor detects the metabolic activity of bacteria via a type of chemical reaction called a <a href="https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:chemical-reactions/x2eef969c74e0d802:oxidation-reduction-redox-reactions/a/oxidation-number">redox reaction</a>. It can detect the oxidation of a molecule that is produced by one of the probiotics. </p>
<h2>Sensor findings</h2>
<p>Before testing, the team first calibrated the sensor using a popular probiotic yogurt widely available in U.S. stores as a model. For each test, we only needed to incubate 100 microliters of sample — about 1/50th of a teaspoon — for 10 minutes at room temperature. </p>
<p>Once we calibrated the sensors, we tested how metabolically active the microorganisms present in the sample were. We tested both beer and yogurt and found that the sensors could determine the metabolic activity more accurately than other tests that scientists usually use. </p>
<p><a href="https://doi.org/10.1002/anse.202300056">We also found</a> that the bacteria in the beer we tested, an unfiltered IPA, had more metabolic activity than the yogurts, which were popular brands Siggi’s, Yakult and Activia.</p>
<p>But, before you run to your local brewery, it’s important to note that the sensor only measures the total metabolic activity of the microorganisms present in the sample. It doesn’t detect anything about the type of activity or potential health effects.</p>
<p>While several groups have reported on the potential <a href="https://doi.org/10.3390%2Fnu15040844">health benefits of beer</a>, not all beers will provide these benefits. And keep in mind that a pint of an IPA carries beneficial bacteria, but also a typical alcohol content of between 6% and 8% and 180-200 calories.</p>
<p>Many <a href="https://doi.org/10.1016/j.tifs.2023.06.013">researchers have performed studies in this field</a> using more traditional probiotic foods that contain many of the microorganisms in your gut. Even in these cases, they’ve found that probiotics’ ability to correct specific health issues is probably limited. </p>
<p>Also, considering the way supplements containing probiotics <a href="https://www.forbes.com/sites/linhanhcat/2019/03/13/probiotics/?sh=35d1926719e8">are regulated</a>, it’s hard to say whether the products actually contain the type and amount of viable bacteria advertised on the label.</p>
<p>All things considered, the proposed sensor aims to provide a simple, portable and low-cost way to detect the activity of live bacteria. These sensors could one day help out in fields like health care.</p><img src="https://counter.theconversation.com/content/219284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Financial support for this project has been provided by the Department of Chemistry at Clemson University and by CAPES (Brazil).</span></em></p><p class="fine-print"><em><span>George Chumanov does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Probiotics are great for your gut, but which sources contain the most beneficial bacteria? Newly developed sensors are helping scientists figure it out.Carlos D. Garcia, Professor of Chemistry, Clemson UniversityGeorge Chumanov, Professor of Chemistry, Clemson UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2197342023-12-15T11:02:43Z2023-12-15T11:02:43ZDiverse gut microbiomes give better protection against harmful bugs – now we know why<figure><img src="https://images.theconversation.com/files/565752/original/file-20231214-21-8x6yy5.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5973%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/child-hands-hold-decorative-model-intestine-2029232825">Helena Nechaeva/Shutterstock</a></span></figcaption></figure><p>In the last decade, it has become increasingly clear that a gut full of friendly microbes (the microbiome) is vital for our good health. It has also become clear that a healthy microbiome is one with a diverse population of microbes (bacteria, viruses, fungi). What we haven’t known is why a diverse array of friendly bugs is important for keeping the harmful microbes (pathogens) at bay. But now we think we have found the answer.</p>
<p>Our <a href="https://www.science.org/doi/10.1126/science.adj3502">latest study</a>, published in Science, shows that the main reason a diverse microbiome is helpful for resisting pathogens is that the friendly microbes collectively consume the nutrients needed for a pathogen to grow in the gut. </p>
<p>In other words, a diverse microbiome blocks pathogen growth by using its nutrients – a phenomenon we call “nutrient blocking”. Understanding how nutrient blocking works is powerful because it allows us to predict which gut communities will be protective against a given pathogen.</p>
<p>Our research team started by conducting a large screen of 100 common strains of human gut bacteria. We tested the individual ability of these strains to restrict the growth of two bacterial pathogens, <em>Klebsiella pneumoniae</em> and <em>Salmonella enterica</em> serovar Typhimurium. These two species are a problem because many strains are becoming resistant to antibiotics. </p>
<p>Alone, the gut strains could not prevent pathogen growth. However, this was different when several of these species were pooled into larger communities. Higher diversity communities tended to offer more protection against invading pathogens, both in test-tube experiments and when tested in mice.</p>
<p>However, not all higher diversity communities tested restricted pathogen growth. Crucially, certain species must be present for a community to be protective. </p>
<p>We then went on to investigate the reason why. We compared the nutrients that could be consumed by each of the individual species with the nutrients consumed by the pathogens. We realised that certain gut species had a higher nutrient use overlap with the pathogens than other species. </p>
<p>Still, individually, the nutrient use overlap of even these key species with the pathogens was not high enough to block pathogen growth. But when we considered which nutrients the community as a whole can use, we found that the communities with the highest degree of overlap with the pathogens provided the most protection.</p>
<h2>Suggesting treatments</h2>
<p>This finding is important as it provides a route for the design of beneficial, probiotic communities that aim to boost the microbiome’s ability to resist colonisation by disease-causing pathogens. </p>
<p>We tested this idea by taking a set of 50 human gut species and predicting which combinations of species would be protective against a new pathogen: a drug-resistant <em>Escherichia coli</em>. </p>
<figure class="align-center ">
<img alt="Scanning electron micrograph of an E coli colony" src="https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565992/original/file-20231215-17-4ya1tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some strains of <em>E coli</em> bacteria (seen here) cause us harm.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=57721205">CDC/Janice Haney Carr</a></span>
</figcaption>
</figure>
<p>We selected the communities that were predicted to be poor at blocking the growth of this pathogenic <em>E coli</em> isolate, and communities that were predicted to be good, and tested them against the new pathogen. In all cases, the nutrient blocking principle was able to successfully predict the ability of the community to block the growth of the pathogen.</p>
<p>Antibiotic treatment failure is <a href="https://theconversation.com/antimicrobial-resistance-is-a-silent-killer-that-leads-to-5-million-deaths-a-year-solutions-must-include-the-poor-217693">becoming more common</a> due to the spread of resistant pathogens. Alternative solutions that harness the body’s natural ability to resist disease, such as by tinkering with the microbiome’s composition, are becoming more attractive. </p>
<p>The gut microbiome is integral to our health, but it is very complex and therefore hard to understand. Our study provides a template for how one might rationally design probiotic communities to engineer microbiomes for better health.</p><img src="https://counter.theconversation.com/content/219734/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frances Spragge received PhD funding from UKRI (BBSRC). </span></em></p><p class="fine-print"><em><span>Erik Bakkeren receives funding from the Swiss National Science Foundation. </span></em></p>Gut bacteria consume the nutrients that harmful pathogens need to survive, thereby keeping them in check, a new study finds.Frances Spragge, DPhil in Microbiology, University of OxfordErik Bakkeren, Postdoctoral Research Fellow, Department of Biology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2188792023-12-11T22:10:48Z2023-12-11T22:10:48ZAntimicrobial resistance now hits lower-income countries the hardest, but superbugs are a global threat we must all fight<figure><img src="https://images.theconversation.com/files/564957/original/file-20231211-23-x9nrkx.jpg?ixlib=rb-1.1.0&rect=907%2C341%2C5083%2C3646&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">While antimicrobial resistance is a threat to all humanity, a tale of two worlds emerges, highlighting the heightened vulnerability of low- and middle-income countries.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/antimicrobial-resistance-now-hits-lower-income-countries-the-hardest-but-superbugs-are-a-global-threat-we-must-all-fight" width="100%" height="400"></iframe>
<p>Antimicrobial resistance (AMR) is one of the World Health Organization’s <a href="https://www.who.int/news-room/photo-story/photo-story-detail/urgent-health-challenges-for-the-next-decade?utm_source=STAT+Newsletters&utm_campaign=1931cb646b-MR_COPY_02&utm_medium=email&utm_term=0_8cab1d7961-1931cb646b-150708293">most urgent health challenges</a> for the next decade. While AMR is a global threat, a tale of two worlds emerges, highlighting the heightened vulnerability of low- and middle-income countries (<a href="https://data.worldbank.org/country/XO">LMICs</a>). </p>
<p>Misuse of antimicrobials worldwide has accelerated the evolution of <a href="https://www.who.int/health-topics/antimicrobial-resistance">antimicrobial resistance</a>. For instance, in many countries, antibiotics are available over the counter, and even when their use is more regulated, the Centers for Disease Control has estimated that in the United States, <a href="https://www.cdc.gov/antibiotic-use/data/outpatient-prescribing/index.html">one in three antibiotic prescriptions</a> were unnecessary. </p>
<p>Likewise, most of the antibiotics are not even given to humans. As much as 80 per cent of the total consumption is <a href="https://doi.org/10.1056/NEJMp1311479">used in livestock</a> to promote growth, and to treat or prevent infections. </p>
<p>This has facilitated bacteria and other microorganisms to become resistant to the drugs that were once effective in treating them — sometimes called <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">superbugs</a>. This problem was associated with <a href="https://doi.org/10.1016/S0140-6736(21)02724-0">4.95 million deaths</a> worldwide in 2019.</p>
<h2>A ‘silent pandemic’</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="clusters of round ivory shapes against a blue background" src="https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564438/original/file-20231208-17-v6wlih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscopic view of methicillin-resistant Staphylococcus aureus (MRSA) bacteria.</span>
<span class="attribution"><span class="source">(NIAID)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>If we don’t take action, things could get even worse. Reports predict that by 2050, AMR could cause <a href="https://amr-review.org/">10 million deaths</a> each year and cost the world <a href="https://www.who.int/news/item/22-06-2023-who-outlines-40-research-priorities-on-antimicrobial-resistance">US$100 trillion</a>. </p>
<p>Fortunately, many nations are now taking decisive steps toward controlling what the WHO calls a “<a href="https://www.who.int/news-room/articles-detail/global-antimicrobial-resistance-forum-launched-to-help-tackle-common-threat-to-planetary-health">silent pandemic</a>.” Acknowledging the gravity of the situation, high-income countries (<a href="https://data.worldbank.org/income-level/high-income">HICs</a>) such as the U.S. and Canada have <a href="https://doi.org/10.1016/S2214-109X(23)00019-0">implemented robust plans</a> encompassing surveillance, stewardship and policy reforms. </p>
<p>These efforts should undoubtedly be applauded. However, an important principle of the “<a href="https://www.who.int/news-room/questions-and-answers/item/one-health">One Health</a>” approach, which is often neglected, is that this is a global problem, and global collaboration should be prioritized. Low- and middle-income countries bear a <a href="https://doi.org/10.1080/14787210.2021.1951705">disproportionate burden</a> of AMR and require increased resource mobilization, knowledge sharing and international co-operation.</p>
<h2>Contrasting realities</h2>
<p>As a doctoral researcher, I study the evolution of antimicrobial resistance in bacteria, but as an immigrant from Mexico, I am deeply concerned with the disparity observed between high-income and low- and middle-income countries, and their contrasting realities. </p>
<figure class="align-center ">
<img alt="A row of three petri dishes with varying levels of growth" src="https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=240&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=240&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=240&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=302&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=302&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564955/original/file-20231211-17-l64ftv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=302&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antimicrobial resistance susceptibility lab tests.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>For instance, there have been great efforts in <a href="https://doi.org/10.1016/S1473-3099(11)70054-8">regulating antibiotic consumption</a> in many HICs, where antibiotic use in livestock has decreased and antibiotics are only accessible under prescription. While there is still room for improvement, there is a less encouraging reality in some LMICs, where antibiotics are usually obtained easily <a href="https://doi.org/10.1016/S1473-3099(11)70054-8">without prescriptions</a> and sometimes used as a way to compensate for the <a href="https://doi.org/10.1080/14787210.2021.1951705">difficulty of accessing health-care professionals</a>. </p>
<p>Likewise, in some LMICs, antibiotic use in animals is predicted to <a href="https://doi.org/10.1073/pnas.1503141112">double by 2030</a> compared to the last decade.</p>
<p>A <a href="https://doi.org/10.1016/j.lana.2023.100594">recent report</a> exploring the burden of AMR in the Americas in 2019 showed the “multiple realities” of the problem. Not surprisingly, by 2019, the four countries with the lowest AMR-linked mortality rates (age-standardized) each had a financed national action plan to combat AMR, while none of the 10 countries with the highest mortality rates did. </p>
<p>Strikingly, <a href="https://www.unicef.org/wash">UNICEF reports</a> that more than half of the world’s population does not have access to safe sanitation and over 2.2 billion people still don’t have access to safe drinking water. This is extremely concerning for a variety of reasons, but good sanitation and hygiene is critical to <a href="https://www.who.int/teams/environment-climate-change-and-health/water-sanitation-and-health/burden-of-disease/wash-and-antimicrobial-resistance#:%7E:text=Improvements%20in%20water%20sanitation%20and,Action%20Plan%20to%20combat%20AMR.">limiting the spread of microbes and reducing the risk of infection</a>.</p>
<p>The current approach taken by most high-income countries is the equivalent of sheltering in the attic, making sure the fire alarm works correctly, while the basement is on fire.</p>
<h2>Worldwide spread</h2>
<figure class="align-right ">
<img alt="Infographic of resistant bacteria spreading around the globe" src="https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564440/original/file-20231208-19-jfdagi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Resistant bacteria or resistance genes can spread across countries through travel, immigration, trade and even water and air circulation.</span>
<span class="attribution"><span class="source">(Centers for Disease Control and Prevention)</span></span>
</figcaption>
</figure>
<p>Resistant bacteria can evolve anywhere. Even if some countries manage to control the problem within their borders, the risk remains. Resistant bacteria or genes that allow bacteria to grow in the presence of the antibiotic can spread across countries through various means, including travel, immigration, trade and even natural processes like water and air circulation. </p>
<p>Such is the case of the resistance gene <a href="https://doi.org/10.1128/aac.00774-09">NDM-1</a>, which was first described in 2009. Only five years after the initial report, this resistance gene was present in virtually the <a href="https://doi.org/10.1111/1469-0691.12719">whole world</a>.</p>
<p>We have all observed the phenomenon of worldwide spread firsthand, as the COVID-19 pandemic vividly demonstrates how pathogens can <a href="https://coronavirus.jhu.edu/map.html">rapidly traverse the globe</a>. </p>
<h2>Communication and collaboration</h2>
<p>It is crucial for nations to enhance communication channels and promote education regarding AMR in several sectors, including the general public, health-care providers, farmers and veterinarians. In addition to this, there is a pressing need to establish robust surveillance systems that can promptly detect outbreaks and enable swift action. </p>
<p>Effective cross-border communication could be realized through standardizing surveillance systems. This would enable accurate comparisons of results between countries. Moreover, it facilitates the sharing of valuable resources, equipment, qualified personnel and access to training opportunities. </p>
<p>Both HICs and LMICs should collaborate closely to implement measures aimed at reducing infection rates, such as improved sanitation practices. This collaboration encourages the exchange of knowledge and expertise, enabling the adoption of best practices globally.</p>
<p>The United Kingdom government set a good example in August, when it allocated <a href="https://www.gov.uk/government/news/210-million-to-tackle-deadly-antimicrobial-resistance">£210 million</a> (about C$360 million) to tackle AMR across Asia and Africa over the next three years, understanding that this threat cannot be fought from its own trenches. These resources will increase surveillance in 25 countries where the AMR threat is highest, and will also be used to upgrade laboratories and strengthen the health workforce in those countries. </p>
<p>To effectively combat AMR, global co-operation is not a luxury but a necessity. HICs must recognize their responsibility to support LMICs in addressing this crisis. By sharing resources, knowledge and expertise, we can collectively mitigate the threat of AMR. </p>
<p>By safeguarding the effectiveness of antibiotics, we protect ourselves and future generations from the devastating consequences of antimicrobial resistance. Together, we can make a difference in the global fight against superbugs.</p><img src="https://counter.theconversation.com/content/218879/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Domínguez has received funding from FRQNT, Concordia University and Mitacs. </span></em></p>The contrasting realities of antimicrobial resistance between high-income countries and low- and middle-income countries demands international co-operation to effectively fight superbugs.Laura Domínguez, Doctoral Researcher and Public Scholar, Biochemistry, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2179202023-11-29T03:33:38Z2023-11-29T03:33:38ZDo you really need antibiotics? Curbing our use helps fight drug-resistant bacteria<p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
<hr>
<p>Antibiotic resistance occurs when a microorganism changes and no longer responds to an antibiotic that was previously effective. It’s <a href="https://thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00502-2/fulltext">associated with</a> poorer outcomes, a greater chance of death and higher health-care costs. </p>
<p>In Australia, antibiotic resistance means some patients are admitted to hospital because oral antibiotics are <a href="https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance">no longer effective</a> and they need to receive intravenous therapy via a drip. </p>
<p>Antibiotic resistance is rising to high levels in certain parts of the world. Some hospitals <a href="https://www.reactgroup.org/news-and-views/news-and-opinions/year-2022/the-impact-of-antibiotic-resistance-on-cancer-treatment-especially-in-low-and-middle-income-countries-and-the-way-forward/">have to consider</a> whether it’s even viable to treat cancers or perform surgery due to the risk of antibiotic-resistant infections.</p>
<p>Australia is <a href="https://www.safetyandquality.gov.au/our-work/antimicrobial-resistance/antimicrobial-use-and-resistance-australia-aura/aura-2023-fifth-australian-report-antimicrobial-use-and-resistance-human-health">one of the highest users</a> of antibiotics in the developed world. We need to use this precious resource wisely, or we risk a future where a simple infection could kill you because there isn’t an effective antibiotic. </p>
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<strong>
Read more:
<a href="https://theconversation.com/the-rise-and-fall-of-antibiotics-what-would-a-post-antibiotic-world-look-like-213450">The rise and fall of antibiotics. What would a post-antibiotic world look like?</a>
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<h2>When should antibiotics not be used?</h2>
<p>Antibiotics only work for some infections. They work against bacteria but <a href="https://www.safetyandquality.gov.au/publications-and-resources/resource-library/do-i-really-need-antibiotics">don’t treat</a> infections caused by viruses. </p>
<p>Most community acquired infections, even those caused by bacteria, are likely to get better without antibiotics. </p>
<p>Taking an antibiotic when you don’t need it won’t make you feel better or recover sooner. But it can increase your chance of side effects like nausea and diarrhoea.</p>
<p>Some people think green mucus (or snot) is a sign of bacterial infection, requiring antibiotics. But it’s actually <a href="https://www.safetyandquality.gov.au/sites/default/files/2023-11/aura_2023_do_i_really_need_antibiotics.pdf">a sign</a> your immune system is working to fight your infection.</p>
<h2>If you wait, you’ll often get better</h2>
<p><a href="https://www.tg.org.au/">Clinical practice guidelines</a> for antibiotic use aim to ensure patients receive antibiotics when appropriate. Yet 40% of GPs say they prescribe antibiotics <a href="https://doi.org/10.1071/HI13019">to meet patient expectations</a>. And <a href="https://pubmed.ncbi.nlm.nih.gov/35973750/">one in five</a> patients expect antibiotics for respiratory infections. </p>
<figure class="align-center ">
<img alt="Man blows nose and looks at thermometre" src="https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562071/original/file-20231128-19-5kijmo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Doctors sometimes tell patients to ‘watch and wait’.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/senior-man-blowing-his-nose-checking-2276021157">Shutterstock</a></span>
</figcaption>
</figure>
<p>It can be difficult for doctors to decide if a patient has a viral respiratory infection or are at an early stage of serious bacterial infection, particularly in children. One option is to “watch and wait” and ask patients to return if there is clinical deterioration. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-antibiotics-arent-always-needed-heres-how-gps-can-avoid-overprescribing-213981">No, antibiotics aren't always needed. Here's how GPs can avoid overprescribing</a>
</strong>
</em>
</p>
<hr>
<p>An alternative is to prescribe an antibiotic but advise the patient to not have it dispensed unless specific symptoms occur. This can <a href="https://doi.org/10.1002/14651858.CD004417.pub5">reduce antibiotic use by 50%</a> with no decrease in patient satisfaction, and no increase in complication rates. </p>
<h2>Sometimes antibiotics are life-savers</h2>
<p>For some people – particularly those with a weakened immune system – a simple infection can become more serious. </p>
<p>Patients with life-threatening suspected infections should receive an appropriate antibiotic <a href="https://www.safetyandquality.gov.au/our-work/clinical-care-standards/antimicrobial-stewardship-clinical-care-standard">immediately</a>. This includes serious infections such as <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/bacterial-meningitis#:%7E:text=What%20is%20bacterial%20meningitis%3F,can%20cause%20life%2Dthreatening%20problems.">bacterial meningitis</a> (infection of the membranes surrounding the brain)
and <a href="https://clinicalexcellence.qld.gov.au/priority-areas/safety-and-quality/sepsis/adult-sepsis#:%7E:text=Adult%20patients%20with%20sepsis%20also,adult%20emergency%20department%20sepsis%20pathway.">sepsis</a> (which can lead to organ failure and even death).</p>
<h2>When else might antibiotics be used?</h2>
<p>Antibiotics are sometimes used to prevent infections in patients who are undergoing surgery and are at significant risk of infection, such as those undergoing bowel resection. These patients will <a href="https://www.tg.org.au">generally receive</a> a single dose before the procedure.</p>
<p>Antibiotics may also <a href="https://www.tg.org.au">be given</a> to patients undergoing chemotherapy for solid organ cancers (of the breast or prostate, for example), if they are at high risk of infection. </p>
<p>While most sore throats are caused by a virus and usually resolve on their own, some high risk patients with a bacterial strep A infection which can cause “scarlet fever” are given antibiotics to prevent a more serious infection like <a href="https://www.rhdaustralia.org.au/">acute rheumatic fever</a>. </p>
<h2>How long is a course of antibiotics?</h2>
<p>The recommended duration of a course of antibiotics depends on the type of infection, the likely cause, where it is in your body and how effective the antibiotics are at killing the bacteria. </p>
<p>In the past, courses were largely arbitrary and based on assumptions that antibiotics should be taken for long enough to eliminate the infecting bacteria. </p>
<figure class="align-center ">
<img alt="Pharmacist handing over antibiotics to a patient" src="https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562075/original/file-20231128-23-l3ap7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The duration of antibiotic courses has shortened.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pharmasict-serving-customer-drug-store-1855116610">Shutterstock</a></span>
</figcaption>
</figure>
<p>More recent research does not support this and shorter courses are <a href="https://www.acpjournals.org/doi/full/10.7326/M19-1509">nearly always as effective as longer ones</a>, particularly for community acquired respiratory infections. </p>
<p>For <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736742/">community acquired pneumonia</a>, for example, research shows a three- to five-day course of antibiotics is at least as effective as a seven- to 14-day course. </p>
<p>The “take until all finished” approach is no longer recommended, as the longer the antibiotic exposure, the greater the chance the bacteria will develop resistance. </p>
<p>However, for infections where it is more difficult to eradicate the bacteria, such as tuberculosis and bone infections, a combination of antibiotics for many months is usually required. </p>
<h2>What if your infection is drug-resistant?</h2>
<p>You may have an antibiotic-resistant infection if you don’t get better after treatment with standard antibiotics. </p>
<p>Your clinician will collect samples for lab testing if they suspect you have antibiotic-resistant infection, based on your travel history (especially if you’ve been hospitalised in a country with high rates of antibiotic resistance) and if you’ve had a recent course of antibiotics that hasn’t cleared your infection. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<p>Antibiotic-resistant infections are managed by prescribing broad-spectrum antibiotics. These are like a sledgehammer, wiping out many different species of bacteria. (Narrow-spectrum antibiotics conversely can be thought of as a scalpel, more targeted and only affecting one or two kinds of bacteria.) </p>
<p>Broad-spectrum antibiotics are usually more expensive and come with more severe side effects.</p>
<h2>What can patients do?</h2>
<p>Decisions about antibiotic prescriptions should be made using <a href="https://www.safetyandquality.gov.au/our-work/partnering-consumers/shared-decision-making/decision-support-tools-specific-conditions">shared decision aids</a>, where patients and prescribers discuss the risks and benefits of antibiotics for conditions like a sore throat, middle ear infection or acute bronchitis.</p>
<p>Consider asking your doctor questions such as:</p>
<ul>
<li>do we need to test the cause of my infection?</li>
<li>how long should my recovery take?</li>
<li>what are the risks and benefits of me taking antibiotics?</li>
<li>will the antibiotic affect my regular medicines?</li>
<li>how should I take the antibiotic (how often, for how long)?</li>
</ul>
<p>Other ways to fight antibiotic resistance include:</p>
<ul>
<li>returning leftover antibiotics to a pharmacy for safe disposal</li>
<li>never consuming leftover antibiotics or giving them to anyone else</li>
<li>not keeping prescription repeats for antibiotics “in case” you become sick again </li>
<li>asking your doctor or pharmacist what you can do to feel better and ease your symptoms rather than asking for antibiotics.</li>
</ul>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>. Listen to the podcast <a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">here</a>.</em></p><img src="https://counter.theconversation.com/content/217920/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Minyon Avent has received funding from the Metro North Hospital and Health Service, the Children’s Hospital Foundation Queensland, the Department of Health, MSD and the Society of Hospital Pharmacists of Australia.</span></em></p><p class="fine-print"><em><span>Fiona Doukas has received funding from the Society of Hospital Pharmacists Australia and Hospira. She works for the Australian Commission on Safety and Quality in Health Care. She is part of an NGO called Hepatitis B Free. She works at two Sydney Hospitals. </span></em></p><p class="fine-print"><em><span>Kristin Xenos works for the Australian Commission on Safety and Quality in Health Care.</span></em></p>Australia is one of the highest users of antibiotics in the developed world. So when do we actually need antibiotics to treat an infection? And when should we avoid them?Minyon Avent, Antimicrobial Stewardship Pharmacist, The University of QueenslandFiona Doukas, PhD candidate, University of SydneyKristin Xenos, Research Assistant, College of Health, Medicine and Wellbeing, School of Biomedical Science and Pharmacy, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2134602023-11-23T19:02:31Z2023-11-23T19:02:31ZDrug resistance may make common infections like thrush untreatable<p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
<hr>
<p>We’ve all heard about antibiotic resistance. This happens when bacteria develop strategies to avoid being destroyed by an antibiotic. </p>
<p>The consequences of antibiotic resistance mean an antibiotic previously used to cure bacterial infections no longer works effectively because the bacteria have become resistant to the drug. This means it’s getting harder to cure the infections some bacteria cause.</p>
<p>But unfortunately, it’s only one part of the problem. The same phenomenon is also happening with other causes of infections in humans: fungi, viruses and parasites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-rise-and-fall-of-antibiotics-what-would-a-post-antibiotic-world-look-like-213450">The rise and fall of antibiotics. What would a post-antibiotic world look like?</a>
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</em>
</p>
<hr>
<p>“Antimicrobial resistance” means the drugs used to treat diseases caused by microbes (bugs that cause infection) no longer work. This occurs with antibacterial agents used against bacteria, antifungal agents used against fungi, anti-parasitic agents used against parasites and antiviral agents used against viruses.</p>
<p>This means a wide range of previously controllable infections are becoming difficult to treat – and may become untreatable. </p>
<h2>Fighting fungi</h2>
<p>Fungi are responsible for a range of infections in humans. Tinea, ringworm and vulvovaginal candidiasis (thrush) are some of the more familiar and common superficial fungal infections. </p>
<p>There are also life-threatening fungal infections such as aspergillosis, cryptococcosis and invasive fungal bloodstream infections including those caused by <em>Candida albicans</em> and <em>Candida auris</em>. </p>
<p>Fungal resistance to antifungal agents is a problem for several reasons. </p>
<p>First, the range of antifungal agents available to treat fungal infections is limited, especially compared to the range of antibiotics available to treat bacterial infections. There are only four broad families of antifungal agents, with a small number of drugs in each category. Antifungal resistance further restricts already limited options.</p>
<p>Life-threatening fungal infections happen less frequently than life-threatening bacterial infections. But they’re rising in frequency, especially among people whose immune systems are compromised, including by <a href="https://7news.com.au/news/qld/first-heart-transplant-patient-to-die-from-fungal-infection-at-brisbanes-prince-charles-hospital-identified-as-mango-hill-gp-muhammad-hussain-c-12551559">organ transplants</a> and chemotherapy or immunotherapy for cancer. The threat of getting a drug-resistant fungal infection makes all of these health interventions riskier.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-candida-auris-and-other-fungi-develop-drug-resistance-a-microbiologist-explains-203495">How do _Candida auris_ and other fungi develop drug resistance? A microbiologist explains</a>
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</em>
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<p>The greatest <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2017.00735/full">burden of serious fungal disease</a> occurs in places with limited health-care resources available for diagnosing and treating the infections. Even if infections are diagnosed and antifungal treatment is available, antifungal resistance reduces the treatment options that will work.</p>
<p>But even in Australia, common fungal infections are impacted by resistance to antifungal agents. Vulvovaginal candidiasis, known as thrush and caused by <em>Candida</em> species and some closely related fungi, is usually reliably treated by a topical antifungal cream, sometimes supplemented with an oral tablet. However, instances of <a href="https://www.theage.com.au/national/victoria/they-can-t-sit-properly-doctors-treat-growing-number-of-women-with-chronic-thrush-20230913-p5e499.html">drug-resistant thrush</a> are increasing, and new treatments are needed.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1584939012753862657"}"></div></p>
<h2>Targeting viruses</h2>
<p>Even <a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">fewer antivirals</a> are available than antibacterial and antifungal agents. </p>
<p>Most antimicrobial treatments work by exploiting differences between the microbe causing the infection and the host (us) experiencing the infection. Since viruses use our cells to replicate and cause their infection, it’s difficult to find antiviral treatments that selectively target the virus without damaging us. </p>
<p>With so few antiviral drugs available, any resistance that develops to one of them significantly reduces the treatment options available. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">Why are there so many drugs to kill bacteria, but so few to tackle viruses?</a>
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</em>
</p>
<hr>
<p>Take COVID, for example. Two antiviral medicines are in widespread use to treat this viral infection: Paxlovid (containing nirmatrelvir and ritonavir) and Lagevrio (molnupiravir). So far, SARS-CoV-2, the virus that causes COVID, has not developed significant resistance to either of these <a href="https://www.cidrap.umn.edu/covid-19/low-levels-resistance-paxlovid-seen-sars-cov-2-isolates">treatments</a>. </p>
<p>But if SARS-CoV-2 develops resistance to either one of them, it halves the treatment options. Subsequently relying on one would likely lead to its increased use, which may heighten the risk that resistance to the second agent will develop, leaving us with no antiviral agents to treat COVID. </p>
<p>The threat of antimicrobial resistance makes our ability to treat serious COVID infections rather precarious.</p>
<h2>Stopping parasites</h2>
<p>Another group of microbes that cause infections in humans are single-celled microbes such as <em>Plasmodium</em>, <em>Giardia</em>, <em>Leishmania</em>, and <em>Trypanosoma</em>. These microbes are sometimes referred to as parasites, and they are becoming increasingly resistant to the very limited range of anti-parasitic agents used to treat the infections they cause. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">Antibiotic resistance: microbiologists turn to new technologies in the hunt for solutions – podcast</a>
</strong>
</em>
</p>
<hr>
<p>Several <em>Plasmodium</em> species cause malaria and anti-parasitic drugs have been the cornerstone of malaria treatment for decades. But their usefulness has been significantly reduced by the <a href="https://www.mmv.org/our-work/mmvs-pipeline-antimalarial-drugs/antimalarial-drug-resistance">development of resistance</a>. </p>
<p><em>Giardia</em> parasites cause an infection called giardiasis. This can resolve on its own, but it can also cause severe gastrointestinal symptoms such as diarrhea, nausea, and bloating. These microbes have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207226/">developed resistance</a> to the main treatments and patients infected with drug-resistant parasites can have protracted, unpleasant infections. </p>
<figure class="align-center ">
<img alt="3D illustration of Giardia lamblia protozoan" src="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Giardia</em> parasites (illustrated here) cause giardiasis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/giardia-lamblia-protozoan-causative-agent-giardiasis-1038065005">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Resistance is a natural consequence</h2>
<p>Treating infections influences microbes’ evolutionary processes. Exposure to drugs that stop or kill them pushes microbes to either evolve or die. The exposure to antimicrobial agents provokes the evolutionary process, selecting for microbes that are resistant and can survive the exposure. </p>
<p>The pressure to evolve, provoked by the antimicrobial treatment, is called “selection pressure”. While most microbes will die, a few will evolve in time to overcome the antimicrobial drugs used against them. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<p>The evolutionary process that leads to the emergence of resistance is inevitable. But some things can be done to minimise this and the problems it brings. </p>
<p>Limiting the use of antimicrobial agents is one approach. This means reserving antimicrobial agents for when their use is known to be necessary, rather than using them “just in case”.</p>
<p>Antimicrobial agents are precious resources, holding at bay many infectious diseases that would otherwise sicken and kill millions. It is imperative we do all we can to preserve the effectiveness of those that remain, and give ourselves more options by working to discover and develop new ones.</p>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>.</em></p><img src="https://counter.theconversation.com/content/213460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christine Carson receives funding from state and federal funding agencies, and the CUREator program, a national biotechnology incubator delivered by Brandon BioCatalyst. She has a commercial interest in companies developing diagnostic tests and preventing viral infections.</span></em></p>We’ve all heard of antibiotic resistance. The same thing is happening with other causes of infections in humans: fungi, viruses and parasites. This is making thrush and other infections hard to treat.Christine Carson, Senior Research Fellow, School of Medicine, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2139812023-11-20T19:00:17Z2023-11-20T19:00:17ZNo, antibiotics aren’t always needed. Here’s how GPs can avoid overprescribing<figure><img src="https://images.theconversation.com/files/559257/original/file-20231114-26-vqpic.jpg?ixlib=rb-1.1.0&rect=718%2C370%2C6543%2C4463&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/candid-shot-black-female-doctor-explaining-2281209513">Shutterstock</a></span></figcaption></figure><p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
<hr>
<p>The growth in antibiotic resistance threatens to return the world to the pre-antibiotic era – with deaths from now-treatable infections, and some elective surgery being restricted because of the risks of infection. </p>
<p>Antibiotic resistance is a major problem worldwide and should be the concern of everyone, including you. </p>
<p>We need to develop new antibiotics that can fight the resistant bacteria or antibiotics that bacteria would not be quickly resistant to. This is like finding new weapons to help the immune system fight the bacteria.</p>
<p>More importantly, we need to use our current antibiotics – our existing weapons against the bacteria – more wisely.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/could-new-antibiotic-clovibactin-beat-superbugs-or-will-it-join-the-long-list-of-failed-drugs-212774">Could new antibiotic clovibactin beat superbugs? Or will it join the long list of failed drugs?</a>
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</p>
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<h2>Giving GPs the tools to say no</h2>
<p>In 2022, more than <a href="https://www.safetyandquality.gov.au/publications-and-resources/resource-library/aura-2023-fifth-australian-report-antimicrobial-use-and-resistance-human-health">one-third of Australians</a> had least one antibiotic prescription, with <a href="https://www.safetyandquality.gov.au/publications-and-resources/resource-library/analysis-2015-2022-pbs-and-rpbs-antimicrobial-dispensing-data">88%</a> of antibiotics prescribed by GPs.</p>
<p>Many people <a href="https://pubmed.ncbi.nlm.nih.gov/28289114/">mistakenly think</a> antibiotics are necessary for treating any infection and that infections won’t improve unless treated with antibiotics. This misconception is found in studies involving patients with various conditions, including respiratory infections and conjunctivitis. </p>
<p>In reality, not all infections require antibiotics, and this belief drives patients requesting antibiotics from GPs. </p>
<p>Other times, GPs give antibiotics because they think patients want them, even when they might not be necessary. Although, in reality they are <a href="https://pubmed.ncbi.nlm.nih.gov/17148626/">after symptom relief</a>. </p>
<p>For GPs, there are ways to target antibiotics for only when they are clearly needed, even with short appointments with patients perceived to want antibiotics. This includes:</p>
<ul>
<li><p>using <a href="https://pubmed.ncbi.nlm.nih.gov/32357226/">decision guides</a> or tests to decide if antibiotics are really necessary</p></li>
<li><p>giving <a href="https://www.safetyandquality.gov.au/our-work/partnering-consumers/shared-decision-making/decision-support-tools-specific-conditions">patients information sheets</a> when antibiotics aren’t needed</p></li>
<li><p>giving a “<a href="https://pubmed.ncbi.nlm.nih.gov/33910882/">delayed prescription</a>” – only to be used after the patient waits to see if they get better on their own. </p></li>
</ul>
<p>All these strategies need some <a href="https://www.nps.org.au/assets/NPS/pdf/NPS-MedicineWise-Economic-evaluation-report-Reducing-Antibiotic-Resistance-2012-17.pdf">training</a> and practice, but they can help GPs prescribe antibiotics more responsibly. GPs can also learn from each other and use tools like <a href="https://pubmed.ncbi.nlm.nih.gov/24474434/">posters</a> as reminders.</p>
<p>To help with patients’ expectations, public campaigns have been run periodically to educate people about antibiotics. These campaigns <a href="https://pubmed.ncbi.nlm.nih.gov/35098267/">explain why</a> using antibiotics too much can be harmful and when it’s essential to take them.</p>
<h2>Giving doctors feedback on their prescribing</h2>
<p>National programs and interventions can help GPs use antibiotics more wisely </p>
<p>One successful way they do this is by <a href="https://pubmed.ncbi.nlm.nih.gov/34356788/">giving GPs feedback</a> about how they prescribe antibiotics. This works better when it’s provided by organisations that GPs trust, it happens more than once and clear goals are set for improvement. </p>
<figure class="align-center ">
<img alt="GP types on laptop" src="https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559258/original/file-20231114-21-ou0m9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">GPs tend to act on feedback about their antibiotic prescribing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/doctor-entering-patient-notes-on-laptop-1033147024">Shutterstock</a></span>
</figcaption>
</figure>
<p>The NPS (formerly National Prescribing Service) MedicineWise program, for example, had been giving feedback to GPs on how their antibiotic prescriptions compared to others. This reduced the number of antibiotics prescribed. </p>
<p>However, <a href="https://australianprescriber.tg.org.au/articles/the-end-of-nps-medicinewise.html">NPS no longer exists</a>. </p>
<p>In 2017, the Australian health department did something similar by sending <a href="https://behaviouraleconomics.pmc.gov.au/projects/nudge-vs-superbugs-behavioural-economics-trial-reduce-overprescribing-antibiotics">feedback letters</a>, randomly using different formats, to the GPs who prescribed the most antibiotics, showing them how they were prescribing compared to others. </p>
<p>The most effective letter, which used pictures to show this comparison, reduced the number of antibiotics GPs prescribed by <a href="https://behaviouraleconomics.pmc.gov.au/sites/default/files/projects/nudge-vs-superbugs-12-months-on-report.pdf">9% in a year</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<h2>Clearer rules and regulations</h2>
<p>Rules and regulations are crucial in the fight against antibiotic resistance. </p>
<p>Before April 2020, many GPs’ computer systems made it easy to get multiple repeat prescriptions for the same condition, which could encourage their overuse. </p>
<p>However, in April 2020, the Pharmaceutical Benefits Scheme (PBS) <a href="https://www.pbs.gov.au/pbs/industry/listing/elements/pbac-meetings/psd/2019-08/antibiotic-repeats-on-the-pharmaceutical-benefits-scheme">changed the rules</a> to ensure GPs had to think more carefully about whether patients actually needed repeat antibiotics. This meant the amount of medicine prescribed better matched the days it was needed for. </p>
<figure class="align-center ">
<img alt="Pharmacist looks at antibiotics" src="https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=377&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=377&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=377&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=474&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=474&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559259/original/file-20231114-27-txxbfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=474&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Simple changes can make a difference to antibiotic prescribing and dispensing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pharmacist-holding-medicine-box-capsule-pack-704036482">Shutterstock</a></span>
</figcaption>
</figure>
<p>Other regulations or policy targets could include: </p>
<ul>
<li><p>ensuring all GPs have access to antibiotic prescribing guidelines, such as <a href="https://www.tg.org.au/">Therapeutic Guidelines</a>, which is well accepted and widely available in Australia</p></li>
<li><p>ensuring GPs are only prescribing antibiotics when needed. Many of the conditions antibiotics are currently prescribed for (such as sore throat, cough and middle ear infections) are self-limiting, meaning they will get better without antibiotics </p></li>
<li><p>encouraging GP working with antibiotics manufacturers to align pack sizes to the recommended treatment duration. The recommended first-line treatments for uncomplicated urinary tract infections in non-pregnant women, for example, are either three days of trimethoprim 300 mg per night or five days of nitrofurantoin 100 mg every six hours. However, the packs contain enough for seven days. This can mean patients take it for longer or use leftovers later. </p></li>
</ul>
<h2>Australia lags behind Sweden</h2>
<p>Australia has some good strategies for antibiotic prescribing, but we have not had a sustained long-term plan to ensure wise use. </p>
<p>Although Australian GPs have been doing well in <a href="https://www.safetyandquality.gov.au/our-work/antimicrobial-resistance/antimicrobial-use-and-resistance-australia-surveillance-system/aura-2021">reducing antibiotic prescribing</a> since 2015, <a href="https://pubmed.ncbi.nlm.nih.gov/35098269/">more</a> could be done. </p>
<p>In the 1990s, Sweden’s antibiotic use was similar to Australia’s, but is now less than half. For more than two decades, Sweden has had a national strategy that reduces antibiotic use by about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5677604/">7% annually</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-can-reverse-antibiotic-resistance-in-australia-heres-how-sweden-is-doing-it-123081">We can reverse antibiotic resistance in Australia. Here's how Sweden is doing it</a>
</strong>
</em>
</p>
<hr>
<p>It is vital Australia invests in a similar long-term national strategy – to have a centrally funded program, but with regional groups working on the implementation. This could be funded directly by the Commonwealth Department of Health and Ageing, or with earmarked funds via another body such as the Australian Centre for Disease Control. </p>
<p>In the meantime, individual GPs can do their part to prescribe antibiotics better, and patients can join the national effort to combat antibiotic resistance by asking their GP: “what would happen if I don’t take an antibiotic?”. </p>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>. Listen to the podcast <a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">here</a>.</em></p><img src="https://counter.theconversation.com/content/213981/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mina Bakhit received funding from Therapeutic Guidelines Ltd (TGL) / Royal Australian College of General Practitioners (RACGP) Foundation Research Grant. </span></em></p><p class="fine-print"><em><span>Paul Glasziou receives funding from an National Health and Medical Research Council (NHMCR) Investigator grant.</span></em></p>Developing new antibiotics is important in the fight against antibiotic resistance. But we also need to use the antibiotics we already have much more wisely – GPs play a major role in this.Mina Bakhit, Assistant Professor of Public Health, Bond UniversityPaul Glasziou, Professor of Medicine, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163722023-11-16T10:12:57Z2023-11-16T10:12:57ZInsects are spreading a devastating plant disease in Italy – Britain must keep it out<figure><img src="https://images.theconversation.com/files/559575/original/file-20231115-27-9hc0jy.jpg?ixlib=rb-1.1.0&rect=0%2C486%2C3954%2C2134&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Olive trees that have died after becoming infected with _Xylella fastidiosa_.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dead-olive-trees-xylella-fastidiosa-1471805759">Fabio Michele Capelli/Shutterstock</a></span></figcaption></figure><p>Since 2013, over 20 million olive trees in Italy have succumbed to a <a href="https://www.bbc.com/future/article/20230111-the-super-sniffer-dogs-saving-italys-dying-olive-trees#:%7E:text=With%20its%2060%20million%20olive,which%20were%20several%20centuries%20old">devastating plant disease</a>. The same disease now threatens many more plant species, across several countries, with the same fate. </p>
<p>Our recent <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0291734">research</a> shows that the insect responsible for inadvertently transmitting the bacteria that cause this disease can feed on a vast number of different plant species. These include many herbaceous plants and trees that are commonly grown in gardens, parks and across the wider countryside in Britain.</p>
<p>During spring, gardeners will often wonder why blobs of spit-like foam have suddenly appeared on their favourite plants. Many will think them unsightly, perhaps even taking time to wash them off, only for the foam to appear again the next day. </p>
<p>This “spittle” is produced by an insect, unimaginatively called a spittlebug, whose juvenile stages immerse themselves in the foam in order to stop drying out and to protect themselves from predators.</p>
<figure class="align-center ">
<img alt="Meadow spittlebug spittle on the branches of Salix." src="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spittle produced by a spittlebug.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aphrophoridae-spittlebugs-family-insects-belonging-order-2000372249">Ihor Hvozdetskyi/Shutterstock</a></span>
</figcaption>
</figure>
<p>There are several species of spittlebug. But one in particular has been shown to smash several entomological records.</p>
<p>The <a href="https://en.wikipedia.org/wiki/Philaenus_spumarius">meadow spittlebug</a> (<em>Philaenus spumarius</em>) can jump with such force that it accelerates faster than any other animal, equivalent to an extraordinary <a href="https://journals.biologists.com/jeb/article/209/23/4607/16474/Jumping-performance-of-froghopper-insects">550 times</a> that of the Earth’s gravity. Even the toughest astronaut will die if faced with an acceleration <a href="https://www.sciencefocus.com/science/whats-the-maximum-speed-a-human-can-withstand">more than eight times</a> that of gravity.</p>
<p>These insects feed by sucking the sap out of plants. A typical adult meadow spittlebug will drink in and then excrete up to <a href="https://www.nytimes.com/2019/02/19/science/spittlebugs-bubble-home.html">200 times its body weight</a> of fluid per day: another record, and the equivalent of an average human excreting 13,000 litres each day. </p>
<p>Most recently, our research has found that this insect has far broader tastes than any other insect known to science; it can feed on over 1,300 species of plant.</p>
<h2>Why does this matter?</h2>
<p>The meadow spittlebug can transmit a bacterium called <em>Xylella fastidiosa</em> that is potentially deadly for the plants on which it feeds. When the spittlebug uses its syringe-like mouthparts to suck out the plant’s sap, the bacteria can get into the tubes that draw fluids up from the roots. Once there, the bacteria proliferate and block these tubes, starving the plant of water. </p>
<p>The symptoms of infection include scorched or stunted leaves. But, as these symptoms can be confused with several other plant problems, such as dehydration, a definitive diagnosis is difficult. To complicate matters further, some infected plants do not show any symptoms, at least not immediately, making them undetected reservoirs of the bacteria.</p>
<p>The bacteria have caused problems on an epic scale in <a href="https://apsjournals.apsnet.org/doi/epdf/10.1094/PHYTO-08-18-0319-FI">Apulia</a>, Italy’s premier olive-growing region. Entire groves of ancient olive trees have died or have been deliberately destroyed to stop the spread of this devastating plant disease.</p>
<p>The <a href="https://food.ec.europa.eu/plants/plant-health-and-biosecurity/legislation/control-measures/xylella-fastidiosa/database-susceptible-host-plants_en">list of plant species</a> that are known to be susceptible to this disease is long and growing. It already includes 690 species across 88 plant families, encompassing not just trees, but many popular garden plants, important horticultural crops and even some arable crops.</p>
<h2>Spittlebugs in Britain</h2>
<p>As part of our research, we asked members of the British public to send us their sightings of spittle. We received over 17,000 responses. Our results suggest that the insect is widespread in almost all British habitats, including gardens, and on an enormously diverse range of plants.</p>
<p>Fortunately, Britain and most of northern Europe are not yet in the grip of this plant disease. But the ubiquitous distribution of the spittlebug vector and its fondness for such a variety of different plants means that if the bacteria were ever accidentally introduced to Britain, it would be able to spread rapidly with potentially devastating consequences.</p>
<p>Scientists in Britain are anxiously watching for signs of any northward spread of the disease on the European continent. It originated in the Americas and was first detected in Apulia, Italy, in 2013, but it has since been <a href="https://www.efsa.europa.eu/en/topics/topic/xylella-fastidiosa#:%7E:text=Official%20surveys%20carried%20out%20by,How%20do%20plants%20become%20infected%3F">reported</a> in southern France, Spain and Portugal. Certain strains of the disease could certainly tolerate cooler northern temperatures, and their spread may be facilitated by our warming climate. </p>
<p><strong>The global distribution of <em>Xylella fastidiosa</em></strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A world map showing the distribution of xylella fastidiosa bacteria." src="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Xylella fastidiosa has not yet been detected in Britain.</span>
<span class="attribution"><a class="source" href="https://gd.eppo.int/taxon/XYLEFA/distribution">EPPO Global Database</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Stopping the spread</h2>
<p>Spittlebugs don’t fly very far so are unlikely to bring the disease into Britain themselves. The most likely entry route would be through plants brought in via the horticultural trade. </p>
<p>Historically, Britain has imported both lavender and olive trees from Italy. However, these plants now have to go through strict importation and quarantine <a href="https://planthealthportal.defra.gov.uk/assets/uploads/UK-Trade-Letter-Feb21-.pdf">controls</a>.</p>
<p>It is critically important that British holidaymakers in Mediterranean countries do not bring home live plant material of any kind. <em>Xylella fastidiosa</em> has not been detected in Britain so far, but the spittlebug’s extraordinarily broad taste in food shows that it would be extremely hard to control if it ever did arrive.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/216372/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Stewart received funding from the UK Biotechnology and Biological Sciences Research Council.</span></em></p><p class="fine-print"><em><span>Claire Harkin received funding from the UK Biotechnology and Biological Sciences Research Council</span></em></p><p class="fine-print"><em><span>Vinton Thompson receives funding from the Biotechnology and Biological Sciences Research Council. </span></em></p>The meadow spittlebug can transmit a deadly bacterium – many plants in Britain could be at risk.Alan Stewart, Professor of Ecology, University of SussexClaire Harkin, Research Associate in the Department of Evolution, Behaviour and Environment, University of SussexVinton Thompson, Research Associate in the Division of Invertebrate Zoology, American Museum of Natural HistoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170252023-11-13T21:44:00Z2023-11-13T21:44:00ZGulf of St. Lawrence: Analyzing fish blood can show us how healthy they are<figure><img src="https://images.theconversation.com/files/557461/original/file-20231003-21-bibw4p.jpeg?ixlib=rb-1.1.0&rect=30%2C12%2C3995%2C3005&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The industrialization of the fishing industry and changes in the environment have raised many issues about the management of our fisheries.</span> <span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>The Gulf of St. Lawrence is an invaluable resource for Canada. Fish and shellfish fisheries that date to the 16th century have remained an essential source of income for many communities, including those on the North Shore and Gaspésie or the Îles-de-la-Madeleine.</p>
<p>For example, in <a href="https://publications.gc.ca/collections/collection_2019/mpo-dfo/Fs124-10-2018-eng.pdf">Îles-de-la-Madeleine</a>, nearly 1,800 jobs (for a total of 12,500 inhabitants) were linked to fishing in 2015.</p>
<p>But the industrialization of fishing, and changes in the environment, have brought about many new problems in the management of our fisheries. The abundance of different fish species in the Gulf has fluctuated greatly over the last 20 years.</p>
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<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
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<p>A case in point: the number of Greenland halibut has declined drastically. This year, <a href="https://www.hi.no/hi/nettrapporter/imr-pinro-en-2023-6">landings</a> are six times lower for fishermen compared to last year.</p>
<p>But other species are benefiting from the situation. This is the case for the population of Atlantic halibut, which is at record levels today.</p>
<p>What is causing these changes? And can we predict further changes?</p>
<p>As a doctoral student in biology at the Institut national de la recherche scientifique (INRS), I am trying to find possible answers to these questions as part of my research work.</p>
<h2>A new health monitoring technique</h2>
<p>The means available for studying the health of fish at the individual level are limited. On the one hand, we can calculate indicators from the weight and height of individual fish. But these measurements are too vague and don’t tell us much.</p>
<p>The logistics of performing biopsies on the tissue of fish — which requires taking samples from their muscle or organs — are complex. To carry them out, researchers must have to travel to the ocean, physically collect samples and bring them back to a laboratory. And then there are ethical considerations, since obviously fish must be sacrificed to achieve this.</p>
<p>Even so, these methods are not very effective for detecting stress induced by environmental changes, and are not effective for detecting stress at early stages, before the physical effects can become manifest.</p>
<p>Yet in a context where the abundance of certain fish species is in rapid decline, an analysis of their overall health is necessary. Fortunately, a new tool is being developed: the <a href="https://www.nature.com/articles/s41598-023-32690-6">circulating microbiome</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="viruses in the blood" src="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551779/original/file-20231003-15-6ou9xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It is often wrongly believed that blood is sterile.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>A little-known practice</h2>
<p>The circulating microbiome is a biomarker, an alarm signal that can be detected in fish even before their health begins to deteriorate. A good biomarker is sensitive, easy to sample, and inexpensive.</p>
<p>The analysis of the circulating microbiome, made up of the DNA of bacteria found in the blood, is directly inspired by <a href="https://theconversation.com/ladn-%20circulating-a-new-simple-and-rapid-weapon-in-the-diagnosis-and-monitoring-of-cancers-206786">similar analyses performed on humans</a>, which provide a great deal of information.</p>
<p>In particular, these analyses make it possible to detect anomalies resulting from the effect of a stress factor on the body, or the development of a disease.</p>
<p>Changes in the environment can also be detected from studying the circulating microbiome. But a major problem emerges here: a fish is not a human. Humans are studied in such detail that knowledge about their health can then be used for an infinite amount of further research. However, sampling fish blood is not a common practice. So there is a great deal that needs to be done before we can properly evaluate the health of fish.</p>
<p>Since the analysis of the circulating microbiome in fish has never been studied before, a lot of work needs to be done to develop the technique.</p>
<h2>Traces of bacteria in the blood?</h2>
<p>As blood circulates throughout the body, it comes into contact specifically with bacteria that make up the other microbiomes (intestinal, oral, dermal). Both in fish and humans, these bacteria are essential for good health.</p>
<p>When we analyze bacterial DNA in the blood, it is therefore possible to find bacteria from the intestine, mouth, or skin. But the hypothesis that these are bacteria specific to the blood cannot be completely ruled out either.</p>
<p>While some continue to believe that blood is sterile, and therefore does not contain any bacteria, we have known since the 1970s that this hypothesis is false — it was confirmed <a href="https://doi.org/10.1128/jcm.39.5.1956-1959.2001">in the 2000s by genomic studies</a>. It’s possible that in 1674, the Dutch microbiologist Antonie Van Leeuwenhoek may even have observed bacteria in salmon blood <a href="https://doi.org/10.3389/fcimb.2019.00148">under a microscope</a>.</p>
<p>Today, we can analyze these bacteria in detail by targeting a very specific bacterial gene, the 16S ribosomal RNA gene. Present in all bacteria around the world, this gene varies slightly from one species to another. That makes it possible to identify and analyze the biodiversity of the microbiome.</p>
<h2>I eat, therefore I am</h2>
<p>Our recent work has made it possible to characterize, for the first time, the <a href="https://www.nature.com/articles/s41598-023-32690-6">circulating microbiomes of turbot and halibut</a>. We have demonstrated that the two fish species have circulating microbiomes dominated by the presence of the species <em>Pseudoalteromonas</em> and <em>Psychrobacter</em>. These bacteria are known to colonize cold environments, for example the bottom of the Gulf of St. Lawrence, which is around 5°C. They are also known to produce bioactive compounds (antibacterials and antifungals). They are more tenacious than other bacteria.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="person with blue gloves holds a fish" src="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551768/original/file-20231003-29-qhulgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Greenland halibut.</span>
<span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>However, differences can be observed between the two species. Turbot has more bacteria called <em>Vibrio</em>, some of which metabolize chitin, a molecule that makes up the shells of the invertebrates on which it feeds. Atlantic halibut, for its part, presents more <em>Acinetobacter</em> bacteria, typical of piscivorous (fish-eating) diets in the intestinal microbiomes. The circulating microbiome in these two fish species therefore seems to be influenced by intestinal bacteria, as is the case in humans. We could therefore potentially link a blood microbiome to the fish’s diet, which is often difficult to estimate.</p>
<h2>An embryonic, but promising technique</h2>
<p>So this first bacterial mapping of the blood of these two species probably reflects their respective intestinal microbiome. From this characterization, detection of a variation in the composition of bacteria could be linked to stress, a change in the environment or a physiological change in the animal.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="comic strip" src="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=907&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=907&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=907&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540859/original/file-20230802-23891-ctgz3u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comic strip illustrating the principle of analyzing the circulating microbiome.</span>
<span class="attribution"><span class="source">(Fanny Fronton)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>For example, we know that in humans, the loss of <em>Actinobacteria</em> in the circulating microbiome is associated with severe acute <a href="https://doi.org/10.3389/fcimb.2018.00005">pancreatitis</a>. And there are dozens of examples like this in humans.</p>
<p>This study, the result of a collaboration between university researchers from INRS, the University of Québec at Rimouski and the Department of Fisheries and Oceans Canada, provides a small overview of the informative potential offered by the blood microbiomes of fish from the Gulf of St. Lawrence.</p>
<p>Further research will make it possible to estimate their health and better predict the evolution of their population. The dramatic collapse of the cod stock in the late 1980s had a major impact on fishermen. Several of them even fear that this situation will happen again with another species. As turbot remains a species at risk, it is essential to ensure better management of St. Lawrence species.</p>
<p>Only by refining our analysis techniques and deepening our scientific knowledge can we prevent this type of collapse from happening again in the future.</p><img src="https://counter.theconversation.com/content/217025/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fanny Fronton received a grant from the Fondation Armand Frappier.</span></em></p>Blood isn’t sterile, and analyzing the bacteria in it could help assess the health of fish and prevent the collapse of their populations.Fanny Fronton, Doctorante en Écologie halieutique et biologie moléculaire, Institut national de la recherche scientifique (INRS)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2134502023-11-07T19:35:17Z2023-11-07T19:35:17ZThe rise and fall of antibiotics. What would a post-antibiotic world look like?<figure><img src="https://images.theconversation.com/files/554665/original/file-20231019-25-r60wx5.jpg?ixlib=rb-1.1.0&rect=11%2C449%2C3982%2C2461&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/woman-in-blue-and-white-polo-shirt-standing-on-yellow-flower-field-during-daytime-CEFYNiM9xLk">Luke Jones/Unsplash</a></span></figcaption></figure><p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
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<p>These days, we don’t think much about being able to access a course of antibiotics to head off an infection. But that wasn’t always the case – antibiotics have been available for less than a century. </p>
<p>Before that, patients would die of relatively trivial infections that became more serious. Some serious infections, such as those involving the heart valves, were <a href="https://pubmed.ncbi.nlm.nih.gov/20173297/">inevitably</a> fatal. </p>
<p>Other serious infections, such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3070694/">tuberculosis</a>, weren’t always fatal. Up to a <a href="https://www.biorxiv.org/content/10.1101/729426v1.full.pdf">half</a> of people died within a year with the most severe forms, but some people recovered without treatment and the remainder had ongoing chronic infection that slowly ate away at the body over many years. </p>
<p>Once we had antibiotics, the outcomes for these infections were much better.</p>
<h2>Life (and death) before antibiotics</h2>
<p>You’ve probably heard of Alexander Fleming’s accidental <a href="https://www.acs.org/education/whatischemistry/landmarks/flemingpenicillin.html">discovery of penicillin</a>, when fungal spores landed on a plate with bacteria left over a long weekend in 1928. </p>
<p>But the <a href="https://www.ox.ac.uk/news/science-blog/penicillin-oxford-story">first patient</a> to receive penicillin was an instructive example of the impact of treatment.
In 1941, Constable Albert Alexander had a scratch on his face that had become infected. </p>
<p>He was hospitalised but despite various treatments, the infection progressed to involve his head. This required removing one of his eyes.</p>
<figure class="align-center ">
<img alt="Old hospital room" src="https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554667/original/file-20231019-29-4a4qra.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In 1941, Albert Alexander was hospitalised with a severe infection.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/furniture-and-fixtures-in-a-hospital-room-13083355/">Jonathan Borba/Pexels</a></span>
</figcaption>
</figure>
<p>Howard Florey, the Australian pharmacologist then working in Oxford, was concerned penicillin could be toxic in humans. Therefore, he felt it was only ethical to give this new drug to a patient in a desperate condition. </p>
<p>Constable Alexander was given the available dose of penicillin. Within the first day, his condition had started to improve. </p>
<p>But back then, penicillin was difficult to produce. One way of extending the limited supply was to “recycle” penicillin that was excreted in the patient’s urine. Despite this, supplies ran out by the fifth day of Alexander’s treatment. </p>
<p>Without further treatment, the infection again took hold. Constable Alexander eventually died a month later.</p>
<p>We now face a world where we are potentially running out of antibiotics – not because of difficulties manufacturing them, but because they’re losing their effectiveness.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/will-we-still-have-antibiotics-in-50-years-we-asked-7-global-experts-214950">Will we still have antibiotics in 50 years? We asked 7 global experts</a>
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</em>
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<h2>What do we use antibiotics for?</h2>
<p>We currently use antibiotics in humans and animals for a variety of reasons. Antibiotics reduce the duration of illness and the chance of death from infection. They also prevent infections in people who are at high risk, such as patients undergoing surgery and those with weakened immune systems. </p>
<p>But antibiotics aren’t always used appropriately. <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30084-0/fulltext">Studies</a> consistently show a dose or two will adequately prevent infections after surgery, but antibiotics are <a href="https://irp.cdn-website.com/d820f98f/files/uploaded/surgical-prophylaxis-prescribing-in-australian-hospitals-results-of-the-2020-surgical-national-antimicrobial-prescribing-survey.pdf">often</a> continued for several days unnecessarily. And sometimes we use the wrong type of antibiotic. </p>
<p><a href="https://irp.cdn-website.com/d820f98f/files/uploaded/antimicrobial-prescribing-practice-in-australian-hospitals-results-of-the-2020-hospital-national-antimicrobial-prescribing-survey.pdf">Surveys</a> have found 22% of antimicrobial use in hospitals is inappropriate. </p>
<figure class="align-center ">
<img alt="Pharmacist looks at label on medicine box" src="https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554669/original/file-20231019-23-xes5p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antibiotics are used for longer than needed and sometimes the wrong type is used.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/woman-in-white-dress-shirt-and-black-pants-standing-near-brown-wooden-shelf-fTQHPb6r4wQ">National Cancer Institute/Unsplash</a></span>
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<p>In some situations, this is understandable. Infections in different body sites are usually due to different types of bacteria. When the diagnosis isn’t certain, we often <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/resp.13334">err</a> on the side of caution by giving broad spectrum antibiotics to make sure we have active treatments for all possible infections, until further information becomes available.</p>
<p>In other situations, there is a degree of inertia. If the patient is improving, doctors tend to simply continue the same treatment, rather than change to more appropriate choice. </p>
<p>In general practice, the issue of diagnostic uncertainty and therapeutic inertia are often magnified. Patients who recover after starting antibiotics don’t usually require tests or come back for review, so there is no easy way of knowing if the antibiotic was actually required. </p>
<p>Antibiotic prescribing can be more complex again if <a href="https://www.mja.com.au/journal/2014/201/2/antibiotic-prescribing-practice-residential-aged-care-facilities-health-care">patients</a> are expecting “a pill for every ill”. While doctors are generally good at educating patients when antibiotics are not likely to work (for example, for viral infections), without confirmatory tests there can always be a lingering doubt in the minds of both doctors and patients. Or sometimes the patient goes elsewhere to find a prescription. </p>
<p>For other infections, resistance can develop if treatments aren’t given for long enough. This is particularly the <a href="https://pubmed.ncbi.nlm.nih.gov/11971765/">case</a> for tuberculosis, caused by a slow growing bacterium that requires a particularly long course of antibiotics to cure. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/tuberculosis-isnt-just-a-historical-disease-heres-how-it-spreads-and-who-is-at-risk-215154">Tuberculosis isn't just a historical disease. Here's how it spreads and who is at risk</a>
</strong>
</em>
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<p>As in humans, antibiotics are also used to prevent and treat infections in animals. However, a proportion of antibiotics are used for growth promotion. In Australia, an <a href="https://www.mja.com.au/journal/2019/211/4/antibiotic-use-animals-and-humans-australia">estimated</a> 60% of antibiotics were used in animals between 2005-2010, despite growth-promotion being phased out.</p>
<h2>Why is overuse a problem?</h2>
<p>Bacteria become resistant to the effect of antibiotics through natural selection – those that survive exposure to antibiotics are the strains that have a mechanism to evade their effects. </p>
<p>For example, antibiotics are sometimes given to <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(18)30279-2/fulltext">prevent</a> recurrent urinary tract infections, but a consequence, any infection that does <a href="https://academic.oup.com/cid/article/73/3/e782/6141409">develop</a> tends to be with resistant bacteria.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/rising-antibiotic-resistance-in-utis-could-cost-australia-1-6-billion-a-year-by-2030-heres-how-to-curb-it-149543">Rising antibiotic resistance in UTIs could cost Australia $1.6 billion a year by 2030. Here's how to curb it</a>
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<p>When resistance to the commonly used first-line antibiotics occurs, we often need to reach deeper into the bag to find other effective treatments. </p>
<p>Some of these last-line antibiotics are those that had been <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202707/">superseded</a> because they had serious side effects or couldn’t be given conveniently as tablets. </p>
<p>New drugs for some bacteria have been developed, but many are much more <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7955006/">expensive</a> than older ones. </p>
<h2>Treating antibiotics as a valuable resource</h2>
<p>The concept of antibiotics as a valuable resource has led to the <a href="https://pubmed.ncbi.nlm.nih.gov/8856755/">concept</a> of “antimicrobial stewardship”, with programs to promote the responsible use of antibiotics. It’s a similar concept to environmental stewardship to prevent climate change and environmental degradation. </p>
<p>Antibiotics are a rare class of medication where treatment of one patient can potentially affect the outcome of other patients, through the transmission of antibiotic resistant bacteria. Therefore, like efforts to combat climate change, antibiotic stewardship relies on changing individual actions to benefit the broader community.</p>
<figure class="align-center ">
<img alt="Surgeon ties her mask" src="https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554670/original/file-20231019-27-9skfki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antimicrobial stewardship relies on individuals making decisions for the greater good.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/woman-in-teal-shirt-wearing-white-mask-8hHxO3iYuU0">SJ Objio/Unsplash</a></span>
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<p>Like climate change, antibiotic resistance is a complex problem when seen in a broader context. Studies have linked resistance to the values and priorities <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(18)30186-4/fulltext">of governments</a> such as corruption and infrastructure, including the availability of electricity and public services. This highlights that there are broader “causes of the causes”, such as public spending on sanitation and health care. </p>
<p>Other <a href="https://academic.oup.com/jac/article/74/9/2803/5512029?login=true">studies</a> have suggested individuals need to be considered within the broader social and institutional influences on prescribing behaviour. Like all human behaviour, antibiotic prescribing is complicated, and factors like what doctors feel is “normal” prescribing, whether junior staff feel they can challenge senior doctors, and even their <a href="https://www.nytimes.com/2016/10/07/upshot/your-surgeon-is-probably-a-republican-your-psychiatrist-probably-a-democrat.html">political views</a> may be important. </p>
<p>There are also issues with the <a href="https://www.cambridge.org/core/journals/international-journal-of-technology-assessment-in-health-care/article/value-assessment-of-antimicrobials-and-the-implications-for-development-access-and-funding-of-effective-treatments-australian-stakeholder-perspective/D45758CFB95520DA4FF06E46135E0628">economic model</a> for developing new antibiotics. When a new antibiotic is first approved for use, the first reaction for prescribers is not to use it, whether to ensure it retains its effectiveness or because it is often very expensive. </p>
<p>However, this doesn’t really <a href="https://academic.oup.com/cid/article/50/8/1081/449089?login=true">encourage</a> the development of new antibiotics, particularly when pharma research and development budgets can easily be diverted to developing drugs for conditions patients take for years, rather than a few days. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-to-change-how-antibiotics-target-bugs-if-we-want-them-to-keep-working-183135">We need to change how antibiotics target bugs if we want them to keep working</a>
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<h2>The slow moving pandemic of resistance</h2>
<blockquote>
<p>If we fail to act, we are looking at an almost unthinkable scenario where antibiotics no longer work and we are cast back into the dark ages of medicine
– <a href="https://amr-review.org/">David Cameron</a>, former UK Prime Minister </p>
</blockquote>
<p>Antibiotic resistance is already a problem. Almost all infectious diseases physicians have had the dreaded call about patients with infections that were essentially untreatable, or where they had to scramble to find supplies of long-forgotten last-line antibiotics. </p>
<p>There are already hospitals in some parts of the world that have had to carefully <a href="https://www.reactgroup.org/news-and-views/news-and-opinions/year-2022/the-impact-of-antibiotic-resistance-on-cancer-treatment-especially-in-low-and-middle-income-countries-and-the-way-forward/">consider</a> whether it’s still viable to treat cancers, because of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6276316/">high risk</a> of infections with antibiotic-resistant bacteria. </p>
<p>A global <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02724-0/fulltext">study</a> estimated that in 2019, almost 5 million deaths occurred with an infection involving antibiotic-resistant bacteria. Some 1.3 million would not have occurred if the bacteria were not resistant. </p>
<p>The UK’s 2014 <a href="https://amr-review.org/sites/default/files/AMR%20Review%20Paper%20-%20Tackling%20a%20crisis%20for%20the%20health%20and%20wealth%20of%20nations_1.pdf">O'Neill report</a> predicted deaths from antimicrobial resistance could rise to 10 million deaths each year, and cost 2-3.5% of global GDP, by 2050 based on trends at that time. </p>
<h2>What can we do about it?</h2>
<p>There is a lot we can do to prevent antibiotic resistance. We can:</p>
<ul>
<li><p><a href="https://www.marketingmag.com.au/news/film-picking-gonorrhoea-wins-tropfest-prize/">raise</a> <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-7258-3">awareness</a> that many infections will get better by themselves, and don’t necessarily need antibiotics </p></li>
<li><p>use the antibiotics we have more appropriately and for as short a time as possible, supported by co-ordinated clinical and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437704/">public policy</a>, and <a href="https://www.amr.gov.au/">national</a> <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00796-4/fulltext">oversight</a> </p></li>
<li><p><a href="https://www.safetyandquality.gov.au/our-work/antimicrobial-resistance/antimicrobial-use-and-resistance-australia-surveillance-system/about-aura-surveillance-system">monitor</a> for infections due to resistant bacterial to inform control policies </p></li>
<li><p>reduce the inappropriate use of antibiotics in animals, such as <a href="https://nam.edu/antibiotic-resistance-in-humans-and-animals/">growth promotion</a> </p></li>
<li><p><a href="https://pubmed.ncbi.nlm.nih.gov/11971765/">reduce</a> cross-transmission of resistant organisms in hospitals and in the community </p></li>
<li><p>prevent infections by other means, such as clean water, <a href="https://apps.who.int/iris/bitstream/handle/10665/204948/WHO_FWC_WSH_14.7_eng.pdf">sanitation</a>, hygiene and <a href="https://www.who.int/teams/immunization-vaccines-and-biologicals/product-and-delivery-research/anti-microbial-resistance">vaccines</a> </p></li>
<li><p>continue developing new antibiotics and alternatives to antibiotics and ensure the right <a href="https://www.thelancet.com/journals/lanepe/article/PIIS2666-7762(23)00124-2/fulltext#:%7E:text=We%20consider%20four%20incentive%20options,exclusivity%20extensions%2C%20and%20milestone%20payments.">incentives</a> are in place to encourage a continuous pipeline of new drugs.</p></li>
</ul>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>.</em></p><img src="https://counter.theconversation.com/content/213450/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Allen Cheng receives funding from the Australian Government and the National Health and Medical Research Council. He is affiliated with the Centre to Impact Antimicrobial Resistance at Monash University. </span></em></p>Antibiotics have been around for less than a century. But as resistant bacteria become increasingly difficult to treat, we risk a greater number of deaths from infections.Allen Cheng, Professor of Infectious Diseases, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.