Plasmid-Mediated Colistin-ResistantEscherichia coliin Bacteremia in Switzerland

Abstract

To the Editor—Very recently the first plasmid-mediated colistin resistance (MCR) mechanism Enterobacteriaceae was reported from animals, food, and patients [ 1–4]. Then a series of short studies, based mainly on retrospective data and established enterobacterial strain collections, reported further identifications of this transmissible colistin-resistant determinant, namely the MCR-1 enzyme, from worldwide. We coauthored reports of a urinary tract infection due to an Escherichia coli strain coexpressing plasmid-mediated carbapenemase and colistin resistance genes [ 5] and a series of MCR-1–positive isolates among a retrospective collection (2004–2005) of E. coli isolates from diarrheic veal calves in France [ 6].