17株耐亚胺培南肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学分析

目的了解17株亚胺培南耐药肺炎克雷伯菌和大肠埃希菌相关耐药基因及分子流行病学状况。方法采用Hodge试验检测碳青霉烯酶表型;采用PCR法检测碳青霉烯酶、I类头孢菌素酶(AmpC)和超广谱β-内酰胺酶(ESBLs)耐药基因,进行测序及网上比对确定基因型;采用肠杆菌科基因间重复序列(ERIC)和多位点序列分型(MLST)对菌株进行同源性和遗传相关性分析。结果 15株肺炎克雷伯菌检出KPC-2、TEM-1、SHV和CTX-M型基因,SHV12和CTX-M-24为主要基因亚型;2株大肠埃希菌检出KPC-2基因,其中1株大肠埃希菌检出TEM-1和CTX-M-24基因,另一株大肠埃希菌检出CMY-42和OXA-1基因;17株菌未检测到IMP、VIM和NDM碳青霉烯酶。15株肺炎克雷伯菌分为A、B和C三个ERIC类别,12株A类为ST11型,2株B类为ST290和ST147型,1株C类为ST967型,2株大肠埃希菌是同一ERIC类别。结论 17株菌亚胺培南耐药主要与KPC-2基因有关,产KPC-2肺炎克雷伯菌在本院神经外科病区呈克隆传播流行,ST11型为此次流行的主要型别;17株菌同时也是产ESBLs株或产ApmC酶株;首次在世界范围内发现ST290和ST967型产KPC-2肺炎克雷伯菌;临床科室应加强院内感染控制措施。

Analysis on molecular epidemiology and related drug-resistance genes of 17 strains of imipenem-resistant K .pneumoniae and E .coli

Objective To investigate the status of molecular epidemiology and related drug‐resistance genes in 17 strains of imipenem‐resistant Klebsiella pneumoniae and Escherichia coli .Methods The carbapenemase pheno‐types were confirmed by the modified Hodge test ;PCR was adopted to detect the resistance genes of carbapenemase , AmpC and ESBLs ,then DNA sequencing was performed and the genotype was determined by internet comparison ;the homology and genetic correlation of isolated strians were detected and analyzed by the enterobacterial repetitive intergenic consensus PCR(ERIC‐PCR) and multiple locus sequence typing (MLST ) .Results KPC‐2 ,TEM‐1 ,SHV and CTX‐M genes were found in 15 strains of K .pneumoniae ,and SHV‐12 and CTX‐M‐24 were predominant geno‐types .KPC‐2 gene was detected in 2 strians of E .coli ,one of which also had TEM‐1 and CTX‐M‐24 gene and another had CMY‐42 and OXA‐1 gene .The carbapenemase genes of IMP ,VIM and NDM were not detected in 17 strains .The homology and genetic relationship analysis revealed that the 15 strains of K .pneumonias were divided into the three ERIC kinds of A ,B and C ,12 strains of class A were ST11 ,2 strains of class B were ST147 and ST290 ,and only 1 strain of C was ST967 ;2 strains of E .colis were the same ERIC kind .Conclusion The imipenem‐resistance of 17 strains is associated with KPC‐2 gene ,KPC‐2‐producing K .pneumoniae strains had clonal transmission and preva‐lence in the neurosurgery wards ,and ST11 type of K .pneumoniae was the predominant clone attributed to this out‐break ;17 strains were the strains of producing ESBLs or AmpC simultaneouly ;This is the first discovery of KPC‐producing K .pneumoniae of ST290 and ST967 in worldwide ;the control measures of nosocomial infection in clinical departments should be enhanced .