In early summer 2008 Timothy Walsh of Cardiff University in Wales got an e-mail from Christian Giske, an acquaintance who is a physician on the faculty of Sweden’s Karolinska Institute. Giske had been treating a 59-year-old man hospitalized that past January in Örebro, a small city about 100 miles from Stockholm. The man had lived with diabetes for many years, suffered several strokes and had lately developed deep bedsores. But those were not the subject of Giske’s message. Instead he was worried about a bacterium that a routine culture had unexpectedly revealed in the man’s urine. Would Walsh, who runs a lab that unravels the genetics of antibacterial resistance, be willing to take a look at the bug?