Get an infection, take an antibiotic. That simple, sensible, and often life-saving intervention, repeated myriad times, has triggered an ever-escalating war between humans and microbes--a war the microbes seem to be winning. Almost as soon as penicillin was introduced in 1942, the bacteria it was designed to defeat began evolving to resist it. Now many common bacteria have acquired resistance to multiple antibiotics, making some infections extraordinarily difficult, if not impossible, to treat.
