Antibiotics and patience

Antibiotics changed medicine more than almost any other invention of the twentieth century. An infection that killed a healthy adult in 1920 became, by 1950, an inconvenience treated in a week. That success created a problem that is now difficult to solve.

Bacteria reproduce quickly and vary as they do so. When a population meets an antibiotic, most die, but any individual that happens to survive passes on whatever made survival possible. Repeat this often enough and the drug stops working, not because the bacteria learned anything, but because the ones that could not survive are gone. This is natural selection running at a speed we can watch.

Human behaviour accelerates it in three ways. Antibiotics are prescribed for viral illnesses, where they cannot help. Courses are stopped early, when the patient feels better but the most resistant bacteria remain. And large quantities are used in farming to make animals grow faster, which maintains a constant selection pressure outside hospitals.

The medical response is partly scientific and partly social. New drugs are difficult to find and expensive to develop, and a new antibiotic earns little because doctors are rightly told to save it for emergencies. Slowing resistance therefore depends on ordinary discipline: accurate diagnosis, completing a course, and not demanding a prescription for a sore throat that would clear by itself.

For students the lesson generalises. Many problems that look technical are really problems of shared behaviour, and are solved by rules that each person finds mildly inconvenient. That is also true of a school platform. Any individual can raise their own score by bending a rule; the rule exists because the system only works if almost nobody does.