产ESBLs大肠埃希菌基因型分析

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-M3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。

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

Objective To understand the distribution and genotypic character of Escherichia coli producing extended spectru beta-lactamases(ESBLs).Methods 151 ESBLs-producing Escherichia coli were determined by 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,accunting 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.