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Antibiotic awareness week

In case you haven’t noticed, this is antibiotic awareness week. Antibiotics have changed our lives more profoundly than almost any other medical intervention outside of vaccination. If you want a glimpse of a world without antibiotics, go and read the following article, I’ll wait.

Imagining the Post-Antibiotics Future

Back again? Disturbing wasn’t it. Antibiotic awareness week seeks to educate people about how threatened these vital medicines are, and what both health professionals and the general public can do to preserve them.

The basic problem is that evolution is smarter than we are.

Humans have isolated and developed a range of cunning chemicals that can kill or disable disease bacteria, but the bacteria evolve mechanisms to bypass or destroy these antibiotics. It’s an evolutionary arms race, we develop a new antibiotic, the bacteria evolve to defeat it in a handful of years, sometimes a mere one or two. We develop another antibiotic and within a few years bacteria have evolved to avoid that one.

It is an arms race we are losing, it can take a decade to develop a new antibiotic which can be defeated in a few years. And developing antibiotics is costly. You won’t get much change from a billion dollars to develop a new antibiotic which will likely be held back to be only used on antibiotic resistant bacteria. There is not much profit in that.

No wonder the number of companies developing antibiotics is dramatically falling, as are the number of new antibiotics licenced. In 1990 there were 18 companies developing new antibiotics, by 2011 there were only 4. In 1990 10 new antibiotics were licenced, in 2011 only 2. While at the same time the tide of resistant bacteria is rising. At the moment 60% of clinically isolated Staphlococcus aureus are resistant to methicillin, in 1990 it was only 25%.

Antibiotic awareness week gives some simple guidelines that can help slow the rise.

For the general public.

1) take your full course of any antibiotic prescribed to you. You may feel better, but there are probably a few resistant bacteria hanging around which can grow up into a problematic resistant population.

2) don’t pressure your GP into giving you antibiotics for colds and flu’s. For otherwise healthy adults uncomplicated viral infections (where you don’t have a bacterial infection on top of the viral infection) are unaffected by antibiotics, you are just providing a breeding ground for bacterial resistance.

The guidelines for health professionals is more comprehensive.

Another thing to look at is the use of antibiotics in agriculture. Nearly 2/3rds of the antibiotics imported into Australia are used as growth promoters. Many are not used in human medicine, but several of these are sufficiently similar to antibiotics used in human medicine to develop cross resistance. This is where bacteria that become resistant to one antibiotic automatically become resistant to a different, but structurally similar, antibiotic.

There is good evidence that some resistant bacteria originated in agricultural use (see also here for another example). A recent Senate enquiry called for urgent action to ensure that human antibiotics are not being used in the agricultural sector.

We can also use evolutionary principles to combat resistance. The use of multi-drug cocktails, a method employed for HIV patients, could help. It often requires a single mutation to develop resistance to an antibiotic. If you teat an infection with two antibiotics, which attack different physiological pathways in the bacteria.

You then need two simultaneous mutations to confer resistance, the likelihood of two simultaneous mutations is much less, and resistance is delayed. However, this kind of treatment will be more expensive for the patient.

So please appreciate antibiotics, they have transformed our lives in the short time we have had them. If the article above doesn’t convince you, take a walk in any old cemetery and the headstones will show you what a world without antibiotics looks like.