碳青霉烯类耐药大肠埃希菌耐药基因型检测及同源性分析

Detection and homology analysis of carbapenem-resistant genotypes of escherichia coli

目的检测临床分离碳青霉烯类耐药大肠埃希菌的耐药基因型,并对其同源性进行分析,研究其流行情况。方法收集铜陵市人民医院2012年9月至2016年10月临床分离碳青霉烯类耐药大肠埃希菌,采用VITEK-2 Compact全自动微生物鉴定仪进行鉴定,改良Hodge试验检测碳青霉烯酶表型,EDTA双纸片协同试验进行金属酶初筛,聚合酶链反应(PCR)检测碳青霉烯酶基因(bla KPC、bla IMP、bla VIM、bla NDM和bla OXA-48),并对阳性扩增产物进行基因测序;同源性分析采用肠杆菌科基因间重复一致序列聚合酶链反应技术(ERIC-PCR)。结果共收集碳青霉烯类耐药大肠埃希菌25株,8株改良Hodge试验阳性,13株金属酶初筛试验阳性,其中4株携带bla NDM-1基因,1株携带bla IMP-4基因,1株携带bla KPC-2基因;ERIC-PCR检测分为10种型别。结论碳青霉烯类耐药大肠埃希菌的耐药机制主要是产金属酶,携带NDM-1型碳青霉烯酶大肠埃希菌需重点监测;碳青霉烯类耐药大肠埃希菌未在医院引起克隆流行。

ObjectivesTo detect the drug-resistant genotypes of clinically isolated carbapenem-resistant Escherichia coli,and analyze their homology to study their epidemic situation.MethodsFrom September 2012 to October 2016,clinically isolated carbapenem-resistant Escherichia coli were collected in Tongling people’s Hospital and identified by VITEK-2 Compact automatic microbiological identification instrument.Modified Hodge test was performed to screen the phenotype of carbapenemase,and metalloenzymes were screened by EDTA double-disc synergistic test.Carbapenemase gene(bla KPC,bla IMP,bla VIM,bla NDM and bla OXA-48)was detected by polymerase chain reaction(PCR).The positive amplified products were sequenced and the homology analysis and typing of ERICPCR were carried out.ResultsA total of 25 strains of carbapenem-resistant Escherichia coli were collected,8 strains were positive for the modified Hodge test,and 13 strains were positive for the metalloenzyme screening test.Four of them carried bla NDM-1 gene,one strain carried blaIMP-4 gene and one strain carried blaKPC-2 gene.ERIC-PCR detection was divided into 10 types.ConclusionsThe main mechanism of carbapenem-resistant Escherichia coli is the production of metalloenzymes.TheNDM-1 type carbapenem-resistant Escherichia coli needs to be monitored.Carbapenem-resistant Escherichia coli did not cause clonal epidemics in hospitals.