Soon after earning his medical degree, Alexander Pym left his home in London to work in a rural hospital in KwaZulu-Natal. From 1992 to 1994, he was in charge of TB control for the hospital’s district of Nqutu. He also launched the hospital’s first voluntary HIV testing programme. When Dr Pym returned to London in 1994 to continue his medical training, he worked on some of the first clinical trials of triple therapy for HIV. He then went on for a PhD at the Institut Pasteur in Paris where he continued his focus on TB, studying the tuberculosis vaccine BCG and the genetic mutations that make the bacterium that causes TB, Mycobacterium tuberculosis, resistant to antibiotics. More recently, he worked at the South African Medical Research Council on clinical drug development. Now based at the KwaZulu-Natal Research Institute for TB-HIV, he has refocused his research on understanding the biological basis of persistence in M. tuberculosis and biomarkers of treatment response, a key requirement for improving treatments for tuberculosis. His laboratory takes a multi-disciplinary approach to this problem, and is developing innovative single cell techniques to study the biology of TB in human samples including sputum and lung.