Characterization of Carbapenem-Resistant Escherichia coli  From a Tertiary Hospital in Hangzhou, China

Background : In recent years, with the large-scale use of antibiotics, the detection rate and mortality of carbapenem-resistant Escherichia coli (CR-EC) have gradually increased. This study explores the molecular characteristics and prevalence of CR-EC isolated from a tertiary hospital in Hangzhou. Methods : A total of 10 non-duplicated CR-EC were collected. The minimal inhibitory concentration was determined by microbroth dilution method. Various drug-resistant genes were detected by polymerase chain reaction. The transferability of plasmid was verified by conjugation test and genetic homology was detected by pulsed-field gel electrophoresis. The whole genome is sequenced using the Illumina MiSeq technology. Results : The strains were of diverse origin and all showed multidrug resistance. bla _NDM was the only detected carbapenem gene with a high carrying rate (80%). The success rate of conjugation was 75%, indicating the horizontal transfer of bla _NDM . Homology analysis showed that there was no widespread cloning outbreak of CR-EC in this study, bla _NDM-5 -ST410 is prevalent in the local area as a dominant group. WGS suggests complex plasmid replicon situations and greater potential risks of drug resistance and virulence. Conclusions : This is a survey on the prevalence and molecular characteristics of CR-EC in the Hangzhou, bla _NDM-like production combined with ESBLs and/or AmpC was the main resistance mechanism of CR-EC. Complex drug resistance, potential virulence risks and the transferability of plasmids have intensified the trend of widespread prevalence of CR-EC, and medical personnel should closely monitor the changes of dominant clone groups (such as ST410) to prevent and control the further spread of CR-EC.