Analysis Of The Molecular Epidemic Characteristics Of Enterobacteriaceae With Carbapenenes And Polymyxin Resistant

Objective To investigate the clinical distribution,drug resistance,phenotype and epidemic characteristics of carbapenem genes of Carbapenem resistant Enterobacteriaceae(CRE),it can help clinicians rationally use antimicrobial agents and effectively control the generation and spread of multidrug-resistant bacteria.Method Using WHONET5.6 software,we count all carbapenem resistant Enterobacteriaceae in our hospital in recent three years.Minimum inhibitory concentrations(MICs)detect drug susceptibility results.For positive strains,the modified Hodge test and EDTA synergy test were preformed to identified the phenotypes of carbapenemases.Carbapenemase and colistin-resistint genes were detected by using PCR amplification and DNA sequencing.Results The 70 strains of CRE were isolated in our hospital from January2014 to December 2016.The main specimen types were bile 29%(20/70)and sputum specimens 23%(16/70).The main clinical departments were concentrated in the Department of hepatobiliary surgery 29%(20/70),followed by PICU and intensive care 11.5%(8/70)and 10%(7/70).In the age distribution,more than 60 years old was the highest,accounted for 42.9%(30/70);followed by 45≤ ~ < 60 years old group 25.7%(18/70).The main strains were Enterobacter cloacae(28/70),followed by Klebsiella pneumoniae(23/70).The resistance rates of penicillins and cephalosporins were up to 90%,and the resistance rate to polymyxin B was the lowest,only 5.7%(4/70).The positive rates of the modifiedHodge test and the EDTA synergy test were 77.1% and 87.1%,respectively.PCR analysis and nucleotide sequencing revealed that the positive rate of bla NDM-1gene was up to 75.7%(53/70),the positive rate of bla KPC-2 and bla IMP-4 genes were 17.1%(12/70)and 11.4%(8/70),respectively.The bla GES-4,bla VIM-2,bla OXA-48 resistance genes and bla MCR-1,bla MCR-2 polymyxin resistance genes were not detected.Most importantly,we detected one co-expressing NDM-1and KPC-2 isolate,one coproduce NDM-1 and IMP-4 strain,and one strain co-harbouring bla KPC-2 and bla IMP-4 genes.Conclusion The detection rate of CRE in our hospital has been increasing year by year.The strain types mainly include Enterobacter cloacae and Klebsiella pneumoniae.The infection age is mostly concentrated in the middle-aged and elderly population.The specimen type is mainly bile and sputum specimens.The distribution of the department is mainly concentrated in Hepatobiliary surgery,PICU and intensive care.The resistance rate of carbapenem antibiotic imipenem is100%,while the resistance rate of aminoglycosides and polymyxins are lower.Other clinical antibacterial drugs showed high drug resistance,especially for penicillins and cephalosporins.The main genotypes were bla NDM-1,followed by bla KPC-2,and bla IMP-4.The bla MCR-1 and bla MCR-2 genes were not found.Therefore,the hospital should pay attention to and strengthen the surveillance of bacterial resistance,so as to prevent the epidemic outbreak of drug-resistant strains infection.