Biosecurity

Behind the scenes of a U.S. superbug discovery that made headlines around the world

Microbiologist Patrick McGann knew he had identified a dangerous germ. He just didn’t know how dangerous.

In mid-May, a colleague had found a strain of E. coli bacteria from a 49-year-old Pennsylvania woman that tested positive for resistance to a drug called colistin. That’s the antibiotic used when all others fail.

McGann, whose job is to prevent outbreaks of new pathogens in the U.S. military’s sprawling health-care system, wasn’t yet alarmed. Sometimes mutations occur spontaneously that make bacteria resistant to an antibiotic. It would be a completely different problem, though, if the bacteria turned out to carry a certain ­colistin-resistant gene called mcr-1.