On Sept. 9, the CDC confirmed the detection of an E. coli strain containing a gene resistant to last-resort antibiotic treatments in a Connecticut pediatric patient. This is the fourth time the "untreatable" bacteria has been detected in the U.S.
The girl developed bloody diarrhea after traveling to the Caribbean for approximately two weeks. The E. coli strain harboring the mcr-1 gene — a gene resistant to a class of antibiotic drugs known as polymyxins — was identified in stool cultures. The E. coli was non-pathogenic and the girl's diarrhea was caused by another type of bacteria, according to CNN.
"She had traveler's diarrhea, probably a parasitic infection, given some of the symptoms, and per normal clinical procedures, they did a stool culture," Maroya Spalding Walters, PhD, CDC epidemiologist and a co-author of the report, told CNN. "Travelers often can pick up these bugs and become 'transiently colonized' as we call it."
Healthy individuals can become colonized with bacteria with the mcr-1 gene without falling ill. People with compromised immune systems could become ill upon coming into contact with the bacteria and healthy people could experience infections if the bacteria were to be introduced into their bloodstream. If the gene were to be transferred to bacteria already resistant to most antibiotics, it would result in the amalgamation of a superbug resistant to all currently available antibiotics.
The mcr-1 gene has previously been detected in three patients from Pennsylvania, New York and New Jersey, and more cases are likely to turn up: In a recently published CDC report on the investigation pertaining to the patient in Pennsylvania, the report's authors wrote, "As more surveillance systems with broader testing are established, it is anticipated that mcr-1 will be identified with increasing frequency."
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