肠道致病大肠杆菌致肠道外感染的研究

发布时间：2018-03-31 15:56

本文选题：大肠杆菌　切入点：血清型　出处：《重庆医科大学》2010年硕士论文

【摘要】： 目的:分析肠道致病大肠杆菌导致肠外感染的细菌学特征以及临床表现。方法:以我院2006—2009年临床分离的227株肠外致病大肠杆菌(Extraintestinal Pathogenic E.coli,ExPEC)为研究对象。用常见肠内致病的肠产毒性大肠杆菌(ETEC)、肠侵袭性大肠杆菌(EIEC)、肠致病性大肠杆菌(EPEC)、肠出血性大肠杆菌(EHEC)的“OK”诊断血清,对上述227株临床分离的ExPEC进行鉴定,发现肠道致病大肠杆菌。然后用PCR进行基因分型和检测肠道致病大肠杆菌的毒力基因,同时用PFGE比较部分患者ExPEC与该患者肠内大肠杆菌的同源性,并结合临床资料分析临床特征。结果:在227株ExPEC中,有34株(20株ETEC, 14株EPEC)肠道致病大肠杆菌。PCR基因分型:A型30株,B1型3株,B2型1株。34株肠道致病大肠杆菌的株毒力基因携带率:ETEC的毒力基因阳性率各为lt 25%、st50%、st/lt20%;EPEC的毒力基因bfpA 71.42%,eaeA 61.42%,eaeA/bfpA 28.57%。PFGE分型:两例败血症患者血培养的大肠杆菌与该患者粪便中分离出的大肠杆菌PFGE分型一致,两患者均有发热、腹泻,血WBC和中性粒细胞异常升高。结论:肠内致病大肠杆菌血清型能够引起临床肠外感染,但所占比例相对较少,且主要为ETEC和EPEC血清型,高龄伴有多基础疾病的住院患者是其感染的高危人群。ETEC感染的败血症患者,其来源可能是患者肠道致病大肠杆菌的移位所致。
[Abstract]:Objective: to analyze the bacteriological characteristics and clinical manifestations of intestinal pathogenic Escherichia coli. Methods: 227 strains of Escherichia coli isolated from 2006 to 2009 in our hospital were studied. The enterotoxigenic Escherichia coli (ETEC), enteroinvasive Escherichia coli (EIEC), enteropathogenic Escherichia coli (E.coli) and enteroectasis were used. The "OK" diagnostic serum of EHEC, Two hundred and two hundred and twenty-two strains of clinical ExPEC were identified and the pathogenic Escherichia coli was found. Then the genotyping and virulence genes of enteric pathogenic Escherichia coli were detected by PCR. At the same time, PFGE was used to compare the homology between ExPEC and Escherichia coli in some patients, and to analyze the clinical characteristics with clinical data. Results: among 227 ExPEC strains, Enteric pathogenic Escherichia coli. PCR genotyping: 30 strains of type A, 30 strains of B 1 strain, 3 strains of B 2 strain. 34 strains of intestinal pathogenic Escherichia coli have virulence gene carrying rate. The virulence gene positive rate of 10% ETEC is the virulence base of EPEC. Because of the typing of bfpA 71.42 and A61.42, the blood culture Escherichia coli of two patients with septicemia was the same as the Escherichia coli PFGE isolated from the feces of the patients. Both patients had fever, diarrhea, abnormal elevation of WBC and neutrophil. Conclusion: the serotype of enteropathogenic Escherichia coli can cause clinical extraintestinal infection, but the proportion is relatively small, and the main serotypes are ETEC and EPEC. Elderly inpatients with multiple underlying diseases are septicemia patients with high risk of infection. ETEC infection may be caused by the translocation of pathogenic Escherichia coli in the intestinal tract of the patients.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R378;R515

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