The Intestinal Carriage of Plasmid-Mediated Colistin-Resistant Enterobacteriaceae in Tertiary Care Settings

In order to estimate the prevalence of plasmid borne colistin resistance and to characterize in detail the -positive isolates, we carried out a sentinel testing survey on the intestinal carriage of plasmid-mediated colistin-resistant Enterobacteriaceae in hospitalized patients. Between June 2018 and September 2019, 1922 faecal samples from hospitalised patients were analysed by selective culture in presence of colistin (3.5 mg/L), and in parallel by direct detection of the to genes by qPCR. The -positive isolates were characterised by whole-genome sequencing. The prevalence of the gene was 0.21% ( = 4/1922); the to genes were not detected. The gene was found to be localised in the IncX4 ( = 3) and IncHI2 ( = 1) plasmid type. One isolate was susceptible to colistin due to the inactivation of the gene through the insertion of the IS2 element; however, the colistin resistance was inducible by culture in low concentrations of colistin. One human positive isolate was related genetically to the isolate derived from turkey meat of Czech origin. -mediated colistin resistance currently poses little threat to patients hospitalised in Czech healthcare settings. The presence of the gene in the human population has a possible link to domestically produced, retail meat.