The colonisation of Czech travellers and expatriates living in the Czech Republic by colistin-resistant Enterobacteriaceae and whole genome characterisation of E. coli isolates harbouring the mcr-1 genes on a plasmid or chromosome: A cross-sectional study

Abstract

BackgroundTravellers were recognized as a risk cohort that can be colonized by mcr-1-mediated colistin-resistant Enterobacteriaceae. We aimed to investigate the carriage of mcr-mediated colistin resistance in Enterobacteriaceae in Czech travellers or expatriates residing temporarily in the Czech Republic. MethodsBetween August 2018 and September 2019, the stool samples were cultured in enrichment broth. The enriched cultures were tested for the presence of the mcr-1-8 genes and inoculated onto selective agar with colistin. Colistin-resistant Enterobacteriaceae were tested for the presence of the mcr-1-8 genes; the mcr-positive isolates were characterised by whole genome sequencing. ResultsFrom the 177 stool samples, 15 colistin-resistant Enterobacteriaceae isolates were cultured (7.9%); two of the E. coli isolates carried the mcr-1 gene (1.1%). In the E. coli multilocus sequence type (ST) 156, the mcr-1 gene was located in an ISApl1-mcr-1-orf-ISApl1 (Tn6330) and incorporated into the chromosome; in the E. coli ST23 isolate, the mcr-1 gene was harboured by the plasmid IncX4. Both of the mcr-1 positive E. coli isolates were multidrug-resistant and one isolate was an extended-spectrum β-lactamase producer (blaCTX-M-27). ConclusionPatients with an international travel history should be monitored for the carriage of the mcr-1 gene in order to prevent its dissemination into healthcare settings.