Escherichia coli strain:O177:H21 Genome sequencing. Escherichia coli strain:O177:H21

The emergence of the newly discovered plasmid-mediated colistin resistance gene, mcr-1, poses a significant threat to hospitalized patients as well as to the community. The aim of this study was to determine the prevalence of mcr-1 mediated colistin resistance gene in fecal samples of patients attending a tertiary care hospital. From November 2014 until July 2015, fecal samples of patients attending the Leiden University Medical Center were collected and retrospectively screened for presence of mcr-1 using real-time PCR. Two of 576 patients were positive for mcr-1, resulting in a prevalence of 0.35%. One sample contained an ESBL negative, AmpC positive and mcr-1 (located on an IncX4 plasmid) containing E.coli. This strain belonged to Sequence Type 359 and serotype O177:H21. The mcr-1 containing E.coli was phenotypically susceptible to colistin with a MIC of ≤ 0.25mg/L, due to a 1329bp transposon IS10R inserted into the mcr-1 gene.