天津医药

天津医药 ›› 2015, Vol. 43 ›› Issue (2): 166-170.doi: 10.11958/j.issn.0253-9896.2015.02.014

• 临床研究 • 上一篇    下一篇

老年患者医院感染的肠外致病性大肠埃希菌毒力因子检测及 SNP 分析

曹阳， 刘双庆， 魏殿军△， 陈薇   

  1. 天津医科大学第二医院检验科(邮编300211)
  • 收稿日期:2014-09-18 修回日期:2014-10-22 出版日期:2015-02-15 发布日期:2015-02-27
  • 通讯作者: 魏殿军 E-mail:ttykcaochen@sina.com
  • 基金资助:
    天津市卫生局科技基金 （2013KZ099）， 天津医科大学第二医院科研基金 （Y1202）

Virulence factors detection and single nucleotide polymorphism assay of extraintestinal pathogenic E.coli in elderly nosocomial infection

  • Received:2014-09-18 Revised:2014-10-22 Published:2015-02-15 Online:2015-02-27

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摘要： 摘要： 目的 了解老年患者医院感染肠外致病性大肠埃希菌 （ExPEC） 30 种毒力因子的检出情况及其分子流行病学特点。方法 收集天津地区引起老年患者医院感染的非重复肠外致病性大肠埃希菌 140 株， 采用多重 PCR 方法检测其毒力因子基因的存在情况， 比较不同标本来源 ExPEC 毒力因子基因的检出率。从检出fimH 基因的菌株中选取 50 株， 进行fimH 基因的扩增与测序， 将全部测序结果与大肠埃希菌对照株 CFT037、 UTI89 和参考株 K-12 Gen⁃ Bank 数据库中的fimH 基因序列均输入软件 DNAMAN 6.0.3.93 中寻找单核苷酸多态性 （SNPs）， 后将 53 个fimH 基因序列输入软件 MEGA4， 进行基因分型和树状图的构建。分型结果结合病例回顾， 综合分析医院内大肠埃希菌克隆流行情况。结果 ExPEC 中毒力因子基因 fimH、 traT、fyuA、 iutA 和 kpsMT II 的检出率较高， 非尿标本来源 ExPEC 的毒力因子基因 kpsM II 、 K5、 papC、 papEF、 papG allele II (Internal)、 papA、 cnf1 (CNF)、 sfa / focDE 和 rfc 的检出率均比尿标本来源 ExPEC 的高。53 株菌fimH 基因 SNPs 分析显示， 在 57 个多态位点中发现有 60 种 SNPs。53 株菌被分为 25 个基因型， 其中有 11 组菌株的基因指纹图谱分别完全一致。未发现不同医院的菌株具有相同的基因型。结论 老年患者医院感染的肠外致病性大肠埃希菌携带多种毒力因子基因； 非尿标本来源的大肠埃希菌可能比尿液标本来源的菌株致病性更强; fimH 基因 SNPs 分型适用于医院大肠埃希菌克隆流行的调查， 值得在今后的临床工作中推广。

关键词: 大肠杆菌, 交叉感染, 毒力因子类, 多态性,单核苷酸, ?mH 基因

Abstract: Abstract： Objective To examine the detection rate of 30 known virulence factors (VFs) of extraintestinal pathogenic Escherichia coli （ExPEC） , and to investigates the epidemiology of ExPEC in elderly nosocomial infection. Methods A to⁃ tal of 140 ExPEC clinical isolates from elderly nosocomial patients in hospitals in Tianjin were investigated. Multiplex PCR was performed to detect the 30 virulence factors among the E.coli strains and the detection rate of virulence factors for Ex⁃ PEC were compared between isolates from different sites of infection．Fifty E. coli strains were shown to carry fimH gene that was amplified and sequenced. These sequences were used besides3 references strains (CFT037、 UTI89 and K-12 ) to detect SNPs of fimH gene using DNAMAN Version 6.0.3.93 these 53 fimH sequences were used for genotyping and building dendrogram by MEGA4 software. Results In ExPEC, the following virulence factor genes, fimH, traT, fyuA, iutA and kpsMT II, had a higher detection rate than those of the rest . The following virulence factor genes, kpsMT II, K5, papC, pa⁃ pEF ,papG allele II (Internal), papA, cnf1 (CNF), sfa / focDE and rfc had a a higher detectionrate from non-urine origin sam⁃ ples than those from urine origin samples. fimH SNPs analysis of the 50 clinical isolated samples and 3 references samples showed 60 SNPs at 57 polymorphic sites. The fimH SNPs analysis classified the 53 strains into 25 genotype. The genetic fin⁃ gerprintings of 11 isolates were exactly the same. Conclusion Many kinds of virulence factors can be found in ExPEC of el⁃ derly nosocomial infection. The ExPEC strain isolated from non-urine origin had a stronger pathogenicity than those from urine-origin specimens. fimH SNPs analysis is suitable for molecular epidemiological investigation of ExPEC in hospital.

Key words: Escherichia coli, cross infection, virulence factors, polymorphism, single nucleotide, fimH gene