CDC and WDH | A urinary tract infection (UTI) caused by multidrug-resistant bacteria carrying the MCR-1 colistin resistance gene was identified in a Wyoming hospital patient in early 2019, researchers from the Centers for Disease Control and Prevention (CDC) and the Wyoming Department of Health (WDH) reported in Morbidity and Mortality Weekly Report (MMWR). The patient had a history of recurrent UTIs. Admission urine culture and antimicrobial susceptibility testing identified the infecting pathogen as carbapenem-resistant Klebsiella pneumoniae with extended-spectrum beta-lactamase production. Further testing identified resistance to 16 antibiotics, as well as colistin, and identified a plasmid-mediated MCR-1 gene. It was not determined where the patient might have acquired the organism. The first US patient carrying MCR-1 was identified in Pennsylvania in July 2016, and since then MCR-1-carrying isolates have been identified in 20 other US states. Colistin is considered a last-resort antibiotic.