Molecular epidemiology of cytolethal distending toxin-producing Escherichia coli

产细胞致死膨胀毒素大肠杆菌的分子流行病学

基本信息

批准号：
15406019
负责人：
YAMASAKI Shinji
金额：
$ 7.23万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15406019/
关键词：
CDT EPEC E.coli ETEC Diarrhea

项目摘要

We have shown that cdtB gene was specifically identified among enteropathogenic E.coli(EPEC). Some of the strains are associated in causing bloody diarrhea among children and exhibited higher production of CDT. The cdtB positive strain mostly belongs to O86a and O127a serogroups. Pulsed-field gel electrophoresis profiles showed that the EPEC strains harboring ctdB were genetically diverse.In this study, 1607 stool specimens were screened for the cdtB harboring enteric pathogens. In the probe hybridization assay, 6 samples (0.4%) were positive and the PCR assay confirmed 5 strains. Form the cdtB probe or PCR positive samples only E.coli strains were isolated and confirmed by serology. Four out of six strains were identified as serogroup O142. Characterization of these strains for different virulence genes specific for diarrheagenic E.coli showed that six strains were enteropathogenic E.coli(EPEC), as they harbored eae as well as bfp genes. We have reported the same trend in our early reports.Expect for two, all the strains harbored cdtA and cdtC genes. These two strains were negative for cdtB by PCR and did not express the CDT in the tissue culture assay. Based on the variation in the sequence of amino acids, the Cdt is classified into CdtI, CdtII and CdtIII. Currently, we are analyzing all our strains to detect the Cdt alleles.Clinical and bacteriological studies have revealed that production of colicin by E.coli having a part of intestinal microbiocenasis is related to the clinical manifestation of inflammatory disease of the gastrointestinal tract. Colicin expression was determined in many enteric pathogens especially among enteropathogenic E.coli(EPEC) and enterohemorrhagic E.coli(EHEC). Colicin expression was confirmed with 3 out of 18 strains (16.7%). There is no correlation between serogroups and colicin expression.

我们已经表明，CDTB基因是在肠病大肠杆菌（EPEC）中特异性鉴定的。一些菌株与儿童引起血腥腹泻有关，并表现出更高的CDT产生。 CDTB阳性菌株主要属于O86A和O127a血清群。脉冲场凝胶电泳曲线表明，携带CTDB的EPEC菌株在遗传上是多样的。在这项研究中，筛选了1607个粪便标本的CDTB含有肠肠病原体。在探针杂交测定中，有6个样品（0.4％）为阳性，PCR分析证实了5个菌株。形成CDTB探针或PCR阳性样品，仅分离出大肠杆菌菌株并通过血清学证实。六个菌株中有四个被确定为血清群O142。这些菌株对腹泻性e.coli特异性的不同毒力基因的表征表明，六种菌株是肠发育性大肠杆菌（EPEC），因为它们具有EAE和BFP基因。我们在早期报告中报告了相同的趋势。所有菌株都有两个菌株和CDTC基因。这两种菌株的CDTB为阴性，在组织培养测定中未表达CDT。基于氨基酸序列的变化，将CDT分类为CDTI，CDTII和CDTIII。目前，我们正在分析所有菌株以检测CDT等位基因。临床和细菌学研究表明，具有一部分具有肠道微生物症的大肠杆菌与胃肠道炎性疾病的临床表现有关。在许多肠道病原体中，尤其是在肠道致病性大肠杆菌（EPEC）和肠肠肠肠肠肠球病原体（EHEC）中确定了菌素的表达。在18种菌株中，有3个（16.7％）证实了菌菌素的表达。血清群与结菌素表达之间没有相关性。