大肠埃希菌产超广谱β-内酰胺酶基因型及毒力因子相关性研究

Relationship between genotype of extended spectrum β-lactamases( ESBLs ) and virulence factors of ESBLs producing E. coli strains

目的分析温州医科大学附属第一医院临床分离产超广谱虞β-内酰胺酶（Extended Spectrum Beta—Lactamase，ESBLs）大肠埃希菌耐药情况，研究大肠埃希菌超广谱β-内酰胺酶的不同基因型与所含的毒力因子的关系。方法普通聚合酶链反应（polymerase chain reaction，PCR）检测不同标本来源大肠埃希菌的毒力因子papC、sfa／foc、afa／dra、iutA、aer、fimH、hly、cnfl、kpsMTII,fyuA；纸片扩散确证法检测超广谱β-内酰胺酶，PCR方法检测ESBLs不同基因型的分布情况。结果产ESBLs大肠埃希菌株中，毒力因子iutA、fyuA的检出率较高，均〉50％；毒力因子fimH、aer的检出率为20％～40％，而毒力因子papC、sfa／foc、afa／dra和kpsMTII的检出率均较低〈20％；经，检验产ESBLs菌株与非产ESBLs菌株的毒力因子分布率差异均无统计学意义（P〉0．5）。92株产ESBLs大肠埃希菌中，毒力因子papC在CTX—M-9群中的阳性率高于TEM群和CTX—M-1群，差异有统计学意义（P〈0．05）；毒力因子aer在CTX—M-1群中的阳性率高于TEM群和CTX—M-9群，差异有统计学意义（P〈0．05）。结论各种毒力因子检出率与细菌是否产ESBLs无相关性。但ESBLs阳性菌株中不同的基因型与某些毒力因子的存在与否存在一定关系，毒力因子与产CTX-M酶大肠埃希菌耐药情况可能有关。

Objective To understand the drug resistance of extended spectrum β-1actamases （ESBLs） producing Escherichia coli strains isolated in our hospital and the relationship between genotype of ESBLs and the virulence factors of ESBLs producing E coli strains Methods PCR was conducted to amplify virulence factors such as papC, sfa / foc, afa / dra, hly, cnfl, iutA, aer, fimH, kpsMTII, fyuA in 188 E. coil strains isolated from inpatients in our hospital. ESBLs was detected with K-B disc diffusion method, the genotype of ESBLs and their distribution were detected by PCR . Results The detection rates of virulence factors iutA andfyuA were all 〉 50%, the detection rats offimH and aer were 20%-40% ,but the detection rate of papC, sfa/foc, afa/dra and kpsMTll were all 〈 20%. There was no significant differences （P 〉 0. 05 ） in virulence factor distribution between ESBLs producing E. coli strains and non ESBLs producing. E. coli strains. Among the 92 ESBLs producing E. coli clinical isolates, the positive rate of papC in CTX-M-9 was higher than that in CTX-M-1 and TEM, the difference was statistical significant （ P 〈 0.05 ） and the positive rate of aer was higher in CTX-M-1 than in TEM and CTX-M-9, the difference was statistical significant （ P 〈 0. 05 ）. Conclusion The detection rate of virulence factor was not associated with ESBLs producing or not in E. coli, but ESBLs genotype was associated with virulence factor. Virulence factor might be associated with the drug resistance of CTX-M producing E. coll.