The Price of Careless Cures

Antibiotics are among the great achievements of modern medicine, but every use of them carries a hidden cost. When a population of bacteria is exposed to an antibiotic, most of the bacteria die, but a few may survive because of chance genetic differences. Those survivors multiply, and over time the population becomes dominated by strains the drug can no longer kill. This is natural selection operating at high speed, and it is accelerated by careless use. Taking antibiotics for a cold or the flu, illnesses caused by viruses that antibiotics do not affect, exposes the body's bacteria to the drug without any benefit. Large-scale use of antibiotics in livestock to speed their growth adds to the pressure. The result is a growing list of infections that are difficult or impossible to treat. Because resistant bacteria cross borders as easily as travelers do, no country can solve the problem alone. Health authorities therefore urge doctors to prescribe more carefully and patients to resist the urge to demand antibiotics for every illness; the medicine that is not taken today may be the medicine that still works tomorrow.