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Resistance Gene Found, Again

An additional patient with bacteria resistant to the antibiotic colistin has been uncovered in the US, according to a report in the Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report. Colistin, it notes, is typically a treatment of last resort for infections that are multidrug-resistant. 

CDC researchers say that the mcr-1 resistance gene was identified from within the whole genome sequence of Escherichia coli isolated from a 2-year-old Connecticut patient. The Associated Press notes that the girl is the fourth person in the US in whom this resistance gene has been found and that officials worry that the resistance gene could spread to bacteria with other resistance profiles.

The girl became ill with fever and bloody diarrhea while visiting family and friends in the Caribbean. Upon her return to the US a few days after her symptoms arose, the CDC researchers note that non-Shiga toxin-producing E. coli O157 was found in her stool samples. The AP says that she likely became ill from something she ate.

But at the same time, she also harbored bacteria with the mcr-1 resistance gene as well as the blacmy-2 gene, which provides resistance to third-generation cephalosporins. The samples were, though, susceptible to carbapenems. The girl was treated with paromomycin, and the infection did not spread to her caregivers.

Previous cases uncovered the mcr-1 resistance gene in patients in Pennsylvania, New Jersey, and New York. The New Jersey patient was resistant to both colistin and carbapenems, the AP notes.