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首页> 外文期刊>BMC Microbiology >Virulence gene profiling of enterohemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli strains: a basis for molecular risk assessment of typical and atypical EPEC strains
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Virulence gene profiling of enterohemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli strains: a basis for molecular risk assessment of typical and atypical EPEC strains

机译:肠出血性(EHEC)和肠致病性(EPEC)大肠埃希菌菌株的毒力基因谱分析:为典型和非典型EPEC菌株进行分子风险评估的基础

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Background Enterohaemorrhagic E. coli (EHEC) can cause severe disease such as bloody diarrhoea and haemolytic uraemic syndrome in humans. Besides production of Shiga toxins, the presence of LEE (eae-gene) and non-LEE (nle) encoded effector genes harboured on O-islands OI-122, OI-71 and OI-57 is associated with EHEC virulence and their frequency in outbreaks. Genes encoded by the EHEC-plasmid are putative virulence markers of EHEC. EHEC-plasmids, LEE and non-LEE effector genes have also been detected in some strains of enteropathogenic E. coli (EPEC). The objective of this study was to analyze the relationship between EHEC and EPEC for virulence genes encoded by genomic O-islands and by the EHEC-plasmids. Results Nle genes ent/espL2, nleB and nleE (OI-122), nleA, nleF and nleH1-2 (OI-71), nleG5-2 and nleG6-2 (OI-57), espK (CP-933N) and the EHEC-plasmid encoded genes ehxA, espP, etpD and katP were searched in 73 typical and in 235 atypical enteropathogenic E. coli (EPEC) strains. Typical and atypical EPEC each fall into two clusters. Cluster 1 typical (n = 46) and atypical (n = 129) EPEC strains were characterized by the presence of OI-122 encoded genes and grouped together with 64 investigated EHEC strains. Cluster 2 typical (n = 27) and atypical (n = 106) strains grouped together with 52 LEE-negative, Shiga toxin-producing E. coli (STEC) and with 21 apathogenic E. coli strains. Typical EPEC Cluster 1 strains belonged to serotypes frequently involved in severe illness and outbreaks in children (O111:H2, O114:H2, O55:H6, O127:H6 and O142:H6). Atypical EPEC Cluster 1 strains were characterized by serotypes related to EHEC (O26:H11, O55:H7, O145:H28, O103:H2 and O103:H25). Conclusion The OI-122 encoded nleB gene was found to be most closely associated with Cluster 1 strains and may serve as a diagnostic tool for the identification of virulent EHEC and EPEC seropathotypes. OI-71 encoded genes nleA, nleF and nleH1-2 are less associated with Cluster 1 strains. EHEC-plasmid, OI-57 and CP-933 associated genes showed only weak similarities with virulent Cluster 1 EHEC and EPEC strains.
机译:背景肠出血性大肠杆菌(EHEC)可能导致人类严重疾病,例如血性腹泻和溶血性尿毒症综合征。除了产生志贺毒素外,在O岛OI-122,OI-71和OI-57上携带的LEE(eae基因)和非LEE(nle)编码的效应基因的存在还与EHEC毒力及其频率有关。爆发。 EHEC质粒编码的基因是EHEC的假定毒力标记。 EHEC质粒,LEE和非LEE效应基因也已在一些肠致病性大肠杆菌(EPEC)菌株中检测到。这项研究的目的是分析基因组O岛和EHEC质粒编码的毒力基因的EHEC和EPEC之间的关系。结果Nle基因ent / espL2,nleB和nleE(OI-122),nleA,nleF和nleH1-2(OI-71),nleG5-2和nleG6-2(OI-57),espK(CP-933N)和EHEC质粒编码的基因ehxA,espP,etpD和katP在73种典型和235种非典型肠致病性大肠杆菌(EPEC)菌株中进行了搜索。典型和非典型的EPEC分为两个类。群集1典型(n = 46)和非典型(n = 129)EPEC菌株的特征在于OI-122编码基因的存在,并与64个研究过的EHEC菌株分组在一起。第2类典型菌株(n = 27)和非典型菌株(n = 106)与52例LEE阴性,产生志贺毒素的大肠杆菌(STEC)和21株致病性大肠杆菌一起分组。典型的EPEC簇1菌株属于经常在儿童中引起严重疾病和暴发的血清型(O111:H2,O114:H2,O55:H6,O127:H6和O142:H6)。非典型EPEC簇1菌株的特征在于与EHEC有关的血清型(O26:H11,O55:H7,O145:H28,O103:H2和O103:H25)。结论发现OI-122编码的nleB基因与Cluster 1菌株最紧密相关,可作为鉴定有毒EHEC和EPEC血清型的诊断工具。 OI-71编码的基因nleA,nleF和nleH1-2与簇1菌株的关联较少。 EHEC质粒,OI-57和CP-933相关基因仅显示与强毒的Cluster 1 EHEC和EPEC菌株的弱相似性。

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