Epdemiology Of Heteroresistance To Imipenem In Enterobacter Cloacae And Risk Factors For Its Acquisition

Objective: Study on infection of cabapenems-heteroresistant Enterobacter cloacae is rare and has not been documented in China.To analyze the Epdemiology and risk factors for infections of imipenem-heteroresistant Enterobacter cloacae(IPM-HR-ECL).Methodes:By means of case-control study,A total of 138 strains of Enterobacter cloacae isolated from the aseptic fluid samples of hospitalized patients from the First Affiliated Hospital of Chongqing Medical University from January 2014 to December 2016 were collected.The disk diffusion was used for screening heteroresistance and PAP test confirmed the heteroresistance.Plulsed Field Gel Electrophoresis(PFGE)was used to analyze the homology of subpopulations.Risk factors for IPM-HR-ECL were statistically analyzed by using the X2 test and logistic regression model.Results:115 out of 138 strains(83.39%)showed heteroresistance to imipenem.The rate of separation of hepatobiliary department was 34.06%.From the type of isolated specimens,most of them were derived from blood samples and the isolation rate was 35.51%.PFGE showed that the original IPM-HR-ECL strian and its one subpopulation had the same clone profile,while the different IPM-HR-ECL strains present clonal diversities.Then retrospective analysis of case data show that malegender,central venous catheter,urinary catheter and use of carbapenems were independent risk factors for the acquisition of IPM-HR-ECL.Conclusion:The IPM-HR phenomenon among the E.cloacae strains is serious and E.cloacae strains showed clonal diversity.Heteroresistance complex the clinical antibiotic therapy.Exposed to a long-term ineffective antibiotic dose may lead heteroresistant bacteria differentiate into fully resistant bacteria,end up with treatment failure.Clinical indications for antimicrobial agents should be strictly controlled and invasive procedures should be regulated to reduce the emergence and prevalence of IPM-HR-ECL bacteria.