Biosecurity

Superbug Source Remains a Mystery

Medical detectives said Friday they are still baffled about how much-feared drug-resistant superbugs infected two people in the U.S. this year, but they have good news: both patients recovered and don't seem to have infected anyone else.

The medical team also reported the fourth known case in the U.S., involving a Connecticut toddler.

The case of a woman in Pennsylvania startled public health officials and made headlines last May.

She was found to be carrying E. coli bacteria that had acquired a gene called mcr-1. This gene gives bacteria the ability to withstand the effects of last-ditch antibiotics.

Luckily, the women recovered and did not appear to infect anyone else, the team at the Pennsylvania Department of Health and the Centers for Disease Control and Prevention reported.