Researchers identified a highly resistant strain of Escherichia coli in four patients at a hospital in New York City, according to a study published in Antimicrobial Agents and Chemotherapy.
The E. coli strain contains a gene called mcr-1, which renders the bacteria resistant to colistin — an antibiotic of last resort for many drug-resistant infections.
Researchers identified the bacteria while monitoring patients with weakened immune systems as part of a prospective surveillance study. Three of the patients harboring the antibiotic-resistant E. coli strain exhibited no symptoms of infection, which increases the risk of unknowingly spreading the bacteria to others.
"While mcr-1 has been described from other parts of the world, it has been very rare in the U.S.," lead author Anne-Catrin Uhlemann, MD, PhD, associate professor at Columbia University's Vagelos College of Physicians and Surgeons in New York City, said in a press release.
"The detection of this cluster demonstrates the potential for silent dissemination of mcr-1 in the U.S. hospital setting, through asymptomatic colonization," Dr. Uhlemann added. "Our findings represent the earliest known documented healthcare-associated cluster of mcr-1 in the United States and predates a recent report that occurred in 2017."