耐碳青霉烯类肠杆菌科细菌耐药基因及分子特征研究

Drug Resistance Genes Analysis and Molecular Characteristics of Enterobacteriaceae with Carbapenem-resistant Antibiotics

目的:探讨临床分离的耐碳青霉烯类抗菌药物肠杆菌科细菌的耐药基因和分子流行病学情况。方法:收集2018年1月—2019年3月临床分离的耐碳青霉烯类肠杆菌科细菌(CRE),采用VITEK-2 compact微生物鉴定仪进行菌种鉴定和药敏检测;改良Hodge和碳青霉烯酶灭活(mCIM)试验对菌株进行碳青霉烯酶表型检测;PCR检测β内酰类胺类(碳青霉烯酶、ESBL、Amp C酶)和喹诺酮类(PMQR)共19种耐药基因;多位点序列分析(MLST)对耐碳青霉烯类肺炎克雷伯菌(CRKP)进行分子分型及同源性分析。结果:共收集CRE 134株,其中肺炎克雷伯菌125株,阴沟肠杆菌4株,大肠埃希菌3株,普罗威登菌2株;改良Hodge试验示114株阳性,碳青霉烯酶灭活(mCIM)试验示125株阳性;所有检测菌株均携带碳青霉烯类耐药基因;125株肺炎克雷伯菌中有118株携带blaKPC-2基因,另有5株携带blaNDM基因(4株携带blaNDM-1、1株携带blaNDM-5)和4株携带blaIMP-4基因,4株阴沟肠杆菌中3株携带blaNDM基因(2株携blaNDM-1、1株携带blaNDM-5),1株携带blaIMP基因,3株大肠埃希菌携带blaNDM基因(2株携带blaNDM-1、1株携带blaNDM-3),2株普罗威登斯菌均携带blaNDM-1基因;所有菌株呈多重耐药现象,耐药谱复杂多样,以blaCTX-M、blaSHV、blaTEM和qnr共同携带最为多见。肺炎克雷伯菌MLST分型以ST11为主(114株)。结论:携带碳青霉烯酶基因是CRE的主要耐药机制,不同菌种携带基因型明显不同,其中肺炎克雷伯菌主要携带blaKPC-2基因,而大肠埃希菌、阴沟肠杆菌及普罗威登菌以携带blaNDM基因为主,表明blaNDM亚型出现并分布于不同菌种间,显示blaNDM进化过程较快,可能成为其广泛传播的重要原因。ST11型是肺炎克雷伯菌的优势流行型别,尤其集中于ICU病区,必须加以重视。

Objective:To investigate the drug resistance genes and molecular epidemiology of clinically isolated carbapenem-resistant antibiotics Enterobacteriaceae.Methods:Collection of carbapenem-resistant Enterobacteriaceae(CRE)bacteria isolated from January 2018 to March 2019,identification and drug susceptibility testing were used by the VITEK-2 compact microbiological analyzer;Modified Hodge and carbapenemase inactivation(mCIM)were used for carbapenemase phenotype detection;a total of 19 drug resistance genes inβ-lactam amines(carbampenalase,ESBL,AmpC enzyme)and quinolones(PMQR)were detected by PCR;molecular typing and homology analysis of carbapenem-resistant Klebsiella pneumoniae(CRKP)were by multi-locus sequence analysis(MLST).Results:A total of CRE 134 strains were collected,including 125 strains of Klebsiella pneumoniae,4 strains of Enterobacter cloacae,3 strains of Escherichia coli,and 2 strains of Providencia;all strains carried carbapenem-resistant genes.Among the 125 strains of Klebsiella pneumoniae,118 strains carried the blaKPC-2 gene,and another 5 strains carried the blaNDM gene(4 strains carrying blaNDM-1,1 strain carrying blaNDM-5)and 4 strains carrying theblaIMP-4 gene,4 strains.Three strains of Enterobacter cloacae carry blaNDM gene(two strains carry blaNDM-1,one strain carries blaNDM-5),one strain carries blaIMP gene,and three strains of Escherichia coli carry blaNDM gene(two strains carry blaNDM-1,one strain carrying blaNDM-3),both strains of Providencia carry the blaNDM-1 gene.All strains are multi-drug resistant,and the drug resistance spectrum is complex and diverse.It is most commonly carried by blaCTX-M,blaSHV,blaTEM and qnr.Klebsiella pneumonia is mainly ST11(114 strains).Conclusion:The carbapenemase gene is the main resistance mechanism of CRE,and the genotypes of different strains are significantly different.Among them,Klebsiella pneumoniae mainly carries blaKPC-2 gene,while Escherichia coli,Enterobacter cloacae and Providencia mainly carry the blaNDM gene,indicating that the blaNDM subtype appears and is distributed among different strains,indicating that the evolution of blaNDM is faster,which may become an important cause of its widespread spread.It must be taken seriously.ST11 is the advantage of the popular type in Klebsiella pneumoniae.