Co-production of MCR-1 and NDM-5 in <em>Escherichia coli</em> isolated from a colonization case of inpatient

Abstract

Colistin is increasingly used as an antibiotic of last resort for treating carbapenem-resistant Enterobacteriaceae. Mobile colistin resistance gene <i>mcr-1</i> has been increasingly reported in Enterobacteriaceae around the world. Of particular concern is the spread of <i>mcr-1</i> into carbapenemase-producing Enterobacteriaceae, which results in highly drug-resistant strains that are potentially untreatable. Notably, such <i>mcr-1</i>-carrying isolates harboring carbapenemase genes have been reported in animals and patients with infection. Here, we report an <i>Escherichia coli</i> strain carrying co-transferable <i>mcr-1</i>-harboring IncX4 and <i>bla</i>_NDM-5-harboring IncX3 plasmids, which was recovered in the context of fecal colonization.