Microbiology. Triple-threat microbe gained powers from another bug.

The long-dreaded superbug surfaced on a summer Friday in 2002. The new strain of Staphylococcus aureus, cultured from foot ulcers on a diabetes patient in a Detroit dialysis center, had developed resistance to vancomycin, one of the few antibiotics left that reliably kills staph. Doctors rushed the strain to the Centers for Disease Control and Prevention in Atlanta, and nine local and CDC public health officials scoured the dialysis center and tested more than 300 people the patient had come in contact with, collecting samples to see if it had spread. It hadn't. "We dodged another bullet," says clinical microbiologist Donald Low of the University of Toronto.