产ESBLs大肠埃希菌基因型分析

Analysis on molecular epidemiological investigation of nosocomial ESBLs-producing Escherichia coli

目的了解医院感染的产超广谱β-内酰胺酶(ESBLs)大肠埃希菌医院感染的临床分布及其基因型特征。方法用表型确证试验确定临床标本中产ESBLs大肠埃希菌151株,应用PCR方法分别扩增产酶菌株的TEM、SHV和CTX-M 3种β-内酰胺酶基因,并对PCR扩增结果及ESBLs株临床分布进行分析。结果PCR扩增结果显示,CTX-M、TEM和SHV基因的阳性率分别为92.10%,49.7%和1.30%;48.3%的菌株同时携带多个基因。产ESBLs大肠埃希菌广泛分布于24个临床科室,其中普外科占23.2%,重症监护病房占10.6%。标本分布较为集中,29.8%来自尿液,24.5%来自呼吸道标本,23.9%来自穿刺液。结论医院感染中,产ESBLs大肠埃希菌的主要基因型是CTX-M,尿液、呼吸道标本、穿刺液是其主要来源,产ESBLs菌分布广泛,需引起重视。

Objective To understand the distribution and genotypic character of Escherichia coli producing extended spectra beta-lactamases （ESBLs）. Methods 151 ESBLs-producing Escherichia coli were determined hy phennotyic confirmatory test according to NCCLS standards. Beta-lactamase genes of TEM, SHV and CTX-M in ESBLs-producing isolates were amplified by PCR, respectively. Results Of all isolates, 92.1%, 49.7 % and 1.3 % were respectively found carrying CTX-M, TEM and SHV gene. In addition, 48.3 % of all strains carrying more than one beta-lactamase gene. ESBL-producing isolates were widely distrbuted over 24 clinical departments. 23.9 % of the isolates were provided from common surgery department and 10.6 % from intensive care unit. Urine and sputum and paracentesis fluid were three kinds of commom samples, aecunting for 29.8 %, 24.5 % and 23.9 %, respectively. Conclusion The predominan genotype of nosocomial ESBLs-producing Escherichia coli was CTX-M. ESBL-producing isolates mostly came from urine, sputum or paracentesis liquid, they were widely prevalent in that hospital.