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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.

我们已经证明cdtB基因在肠致病性大肠杆菌（EPEC）中被特异性地鉴定。一些菌株与引起儿童血性腹泻有关，并表现出较高的CDT产量。cdtB阳性菌株主要属于O86a和O127a血清群。脉冲场凝胶电泳图谱显示携带ctdB的EPEC菌株具有遗传多样性。探针杂交法检测阳性6例（0.4%），PCR法检测阳性5例。从cdtB探针或PCR阳性样品中，仅分离大肠杆菌菌株并通过血清学确认。6个菌株中有4个被鉴定为血清群O142。对这些菌株的不同致病性大肠杆菌特异性毒力基因的表征表明，6种菌株为肠致病性大肠杆菌（EPEC），因为它们携带eae和bfp基因。我们在早期的报道中也报道了同样的趋势，除了两个菌株外，所有菌株都携带cdtA和cdtC基因。这两个菌株通过PCR对cdtB是阴性的，并且在组织培养测定中不表达CDT。根据氨基酸序列的变化，Cdt分为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，具有部分肠道微生物菌群的大肠杆菌产生大肠杆菌素与胃肠道炎性疾病的临床表现有关。在许多肠道病原体中确定了大肠杆菌素表达，特别是在肠致病性大肠杆菌（EPEC）和肠出血性大肠杆菌（EHEC）中。大肠杆菌素的表达被证实与18株（16.7%）的3。血清群与大肠杆菌素表达之间没有相关性。