Superbugs: An Arms Race Against Bacteria by William Hall, Anthony McDonnell, and Jim O’Neill Harvard University Press, 246 pp., $29.95

I never knew my aunt, Pessimindle. As a teenager in the early 1900s, she developed appendicitis and rapidly succumbed to the infection. At the time, there were no antibiotics. When I was growing up, my father contrasted the loss of his sister with the advent of penicillin that saved many of his fellow soldiers in the waning days of World War II. I was taught that medicine could create miracles, which should never be taken for granted.

Penicillin was serendipitously discovered when the researcher Alexander Fleming went on vacation in the summer of 1928. He returned to his laboratory at St. Mary’s Hospital, London, to find that a petri dish with bacteria had been left open and had become contaminated by a relatively rare strain of airborne mold, Penicillium notatum, its spores likely drifting in through the window. The growth of the bacteria in the dish was inhibited by the mold. Its inhibitory substance, termed penicillin, was produced in scant quantities and was laborious to purify. A worldwide search was launched to find other strains of Penicillium that produced higher concentrations; promising samples were obtained in Cape Town, Mumbai, and Chongqing, but the best came from an overripe melon bought at a fruit market in Peoria. Pharmaceutical companies scaled up production of the antibiotic and, beginning with the D-Day landings in 1944, it was widely available to Allied troops.

Fleming recognized not only the opportunity afforded by the open petri dish, but also the peril from misusing the drug. In his speech accepting the 1945 Nobel Prize in Physiology or Medicine he said:

The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant. Here is a hypothetical illustration. Mr. X has a sore throat. He buys some penicillin and gives himself, not enough to kill the streptococci but enough to educate them to resist penicillin. He then infects his wife. Mrs. X gets pneumonia and is treated with penicillin. As the streptococci are now resistant to penicillin the treatment fails. Mrs. X dies. Who is primarily responsible for Mrs. X’s death? Why Mr. X, whose negligent use of penicillin changed the nature of the microbe. Moral: If you use penicillin, use enough.

Fleming’s advice to use the antibiotic properly was widely disregarded, not by “the ignorant man” but by “negligent” medical professionals. Prescriptions of penicillin in suboptimal dosages led to the emergence of bacteria resistant to it.

This is because bacteria reproduce at an astonishing rate. E. coli, commonly found in our colon, has a generational interval of about twenty minutes. Homo sapiens has an average generational interval of thirty…