antimicrobial resistance

Antimicrobial resistance happens when bacteria, viruses, fungi and parasites stop responding to the medicines designed to treat them. The World Health Organization is precise about where the change takes place: it is the microbe that changes, not the person taking the drug. A course of antibiotics kills the bacteria it can, and any that survive through some quirk of their biology go on to multiply. Over enough courses, in enough people, the survivors become the population.

The consequence is that infections which were once routine to treat become difficult or impossible, raising the risk of spread, severe illness, disability and death. WHO estimates that resistance in bacteria alone was associated with more than 4.7 million deaths worldwide in 2021. It is driven by taking these medicines when they are not needed or not taking them correctly, by poor sanitation and weak infection control in hospitals and on farms, and by too few new drugs arriving to replace the ones that have stopped working.