The Centers for Disease Control and Prevention (CDC) is collaborating in a coordinated public health response to the discovery of the first mcr-1 gene found in bacteria from a human in the United States. Escherichia coli (E. coli) bacteria carrying the mcr-1 gene were found in a urine sample from a person in Pennsylvania with no recent travel outside of the United States who presented to a clinic with a urinary tract infection. The mcr-1 gene makes bacteria resistant to the antibiotic colistin, which is used as a last-resort drug to treat patients with infections caused by multidrug-resistant bacteria, including carbapenem-resistant Enterobacteriaceae (CRE). The mcr-1 gene exists on a plasmid, a small piece of DNA that is capable of moving from one bacterium to another, potentially spreading antibiotic resistance to other bacterial species. CDC is reminding healthcare facilities of the importance of measures to prevent transmission of antibiotic resistant bacteria. Read the CDC health advisory.