In a report published Thursday in The Lancet Infectious Diseases, a U.K.-based medical journal, the scientists wrote that they'd found colistin-resistant bacteria on a Chinese pig farm. Later, they observed the resistant bacteria in raw meat and even humans.
Colistin, a 50-year-old drug used on animals more than humans, is given to people only when all other antibiotics have proven ineffective.
The resistant mutation, dubbed the MCR-1 gene, was found in one-fifth of the 804 animals observed. It also showed up in 15 percent of the 523 raw meat samples and in 1 percent of the 1,332 patients observed in the roughly three-year study.