Thanks to Greg Folkers for sending the link to this report in JAMA: Infectious Disease Expert Sees Threat From Colistin-Resistant Superbug. Excerpt:
Scientists at the Walter Reed Army Institute of Research (WRAIR) and the Walter Reed National Military Medical Center recently published a troubling finding: Escherichia coli carrying a gene conferring resistance to the antibiotic colistin in the urine of a Pennsylvania woman (McGann P et al. Antimicrob Agents Chemother. 2016;60:4420-4421). It was the first time the gene, mcr-1, had been found in a human bacterial infection in the United States.
Mcr-1 thwarts colistin, a 1950s-era antibiotic called out of retirement to treat multidrug-resistant infections including carbapenem-resistant Enterobacteriaceae. Even more concerning, the gene is carried on a plasmid, a short, circular strand of nonchromosomal DNA that can transfer to other types of bacteria, spreading its potentially lethal resistance.
Scientists reported the discovery of the gene in China just last year (Liu YY et al. Lancet Infect Dis. 2016;16:161-168). By then, it was already widespread in E coli and Klebsiella pneumoniae, two species of Enterobacteriaceae, found in a number of pigs and patients in South China. Enterobacteriaceae is a family of gram-negative bacteria that also includes Salmonella, Shigella, and Yersinia pestis (plague).
The gene has now been detected in livestock, meat, and people on most continents (Skov R, Monnet D. Euro Surveill. 2016;21:1-6). In July, a second case of E coli with the mcr-1 gene was reported in a human patient in New York (Castanheira M et al. Antimicrob Agents Chemother. doi:10.1128/AAC.01267-16 [published online July 11, 2016]).
News of the superbug in US patients came as no surprise to Barbara E. Murray, MD, director of the division of infectious diseases at the University of Texas Health Science Center at Houston and an internationally recognized expert on antibiotic resistance.
“Once [resistance has] appeared somewhere, you know it’s going to appear other places, so it was just a matter of time,” said Murray, a past president of the Infectious Diseases Society of America. “I’ve been working on antibiotic resistance for 30 years, and it always happens [this way].”