Long-Dreaded Superbug Found in Human and Animal in U.S.

The antibiotic resistance factor MCR, which protects bacteria against the final remaining drugs of last resort, has been found in the United States for the first time—in a person, and separately, in a stored sample taken from a slaughtered pig.  A 49-year-old woman who sought medical care at a military-associated clinic in Pennsylvania last month, with what seemed to be a urinary tract infection, was carrying a strain of E. coli that’s resistant to a wide range of drugs. That turned out to be because the organism carried 15 different genes conferring antibiotic resistance, clustered on two “mobile elements” that can move easily among bacteria. One element included the new, dreaded gene mcr-1.