In late November, researchers in China published their findings of bacteria in pigs, broiler chickens and humans, containing a gene that makes it resistant to all forms of antibiotics, including "last resort" drugs used to beat the toughest antimicrobial resistant bugs. The gene responsible for resistance was mcr-1, and was also identified in Denmark by researchers last week.
The gene has been found in E. coli and Klebsiella pneumonia bacteria, according to the Chinese research, published in The Lancet Infectious Diseases. Colistin, the last resort drug that has proven ineffective on bacteria containing the mcr-1 gene, came into widespread use after bacteria began to develop resistance to a group of drugs called carbapenems, which had been used to tackle complex infections in hospitals, according to a National Geographic report. Colistin is inexpensive and commonly used in agriculture. The ensuing rise in its prescription following growing carbapenem-resistance likely contributed to the ability of mcr-1 to protect bacteria from it.
Frank Aarestrup, head of the genomic epidemiology group at the National Food Institute in Denmark where the resistant bacteria was discovered, told STAT he had sincerely hoped it wouldn't happen, but was unsurprised by the findings. He also urged other researchers with whole genome sequencing databases to begin looking for bacteria containing the gene immediately.