When the drugs don’t work

SOME people describe Darwinian evolution as “only a theory”. Try explaining that to the friends and relatives of the 700,000 people killed each year by drug-resistant infections. Resistance to antimicrobial medicines, such as antibiotics and antimalarials, is caused by the survival of the fittest. Unfortunately, fit microbes mean unfit human beings. Drug-resistance is not only one of the clearest examples of evolution in action, it is also the one with the biggest immediate human cost. And it is getting worse. Stretching today’s trends out to 2050, the 700,000 deaths could reach 10m.Cynics might be forgiven for thinking that they have heard this argument before. People have fretted about resistance since antibiotics began being used in large quantities during the late 1940s. Their conclusion that bacterial diseases might again become epidemic as a result has proved false and will remain so. That is because the decline of common 19th-century infections such as tuberculosis and cholera was thanks to better housing, drains and clean water, not penicillin.