Identification Of Four Patients With Colistin-Resistant Escherichia Coli Containing The Mobile Colistin Resistance Mcr-1 Gene From A Single Health System In Michigan

Clinical Enterobacteriacae isolates with a colistin minimum inhibitory concentration (MIC) >= 4 mg/L from a United States hospital were screened for the mcr-1 gene using real-time polymerase chain reaction (RT-PCR) and confirmed by whole-genome sequencing. Four colistin-resistant Escherichia coli isolates contained mcr-1. Two isolates belonged to the same sequence type (ST-632). All subjects had prior international travel and antimicrobial exposure.