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首页> 外文期刊>Infection and immunity >Escherichia coli serogroup O111 includes several clones of diarrheagenic strains with different virulence properties.
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Escherichia coli serogroup O111 includes several clones of diarrheagenic strains with different virulence properties.

机译：大肠杆菌O111血清群包括几个具有不同毒力特性的腹泻菌株的克隆。

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Genetic variation among isolates of Escherichia coli O111 obtained mostly from patients with diarrhea in Brazil was assessed by multilocus enzyme electrophoresis to characterize chromosomal genotypes and by gene probes and adherence assays to characterize virulence properties. Among the 152 isolates, we resolved 16 distinct electrophoretic types (ETs), which differed on average at 40% of the enzyme loci. We identified four major bacterial O111 clones of different disease classes: ET 12, which includes the bulk of the enteropathogenic E. coli strains, typically showing localized adherence and intimate attachment in tissue culture assays; ET 1, which includes strains with a different set of virulence markers; ET 9, which includes strains that show intimate attachment but lack localized adherence and Shiga-like toxin genes; and ET 8, which includes strains that are Shiga-like toxin producers and have the corresponding traits of enterohemorrhagic E. coli. Enteroaggregative strains constituted ET 10 and also occurred in ET 1. Isolates of the major clones were found in South and North America and matched in ET and virulence factors to previously described diarrheagenic clones that are widely disseminated in the human population. Because the major clones are genetically distantly related and exhibit different combinations of virulence factors, we hypothesize that they have distinct mechanisms of pathogenesis. The results indicate that genetic divergence of bacteria with the O111 antigen, as measured by allelic variation in enzyme loci, is accompanied by divergence in virulence properties of clones so that identification and classification of pathogenic E. coli strains cannot be based solely on serotyping or a single virulence factor.
机译：通过多位点酶电泳来表征染色体基因型，并通过基因探针和粘附试验来表征毒力特性，从而评估了从巴西腹泻患者中获得的大肠杆菌O111分离株之间的遗传变异。在152个分离物中，我们解析了16种不同的电泳类型（ET），其平均差异为酶基因座的40％。我们鉴定了四个不同疾病类别的主要O111细菌克隆：ET 12，包括大部分致肠病性大肠杆菌菌株，在组织培养分析中通常表现出局部粘附和紧密附着; ET 1，包括带有不同毒力标记集的菌株; ET 9，包括表现出紧密附着但缺乏局部粘附和志贺样毒素基因的菌株;和ET 8，其包括志贺样毒素产生者的菌株，并具有相应的肠出血性大肠杆菌特征。肠聚集菌构成ET 10，也出现在ET 1中。主要克隆的分离株在南美和北美洲发现，并且在ET和致病因子方面与先前描述的在人类人群中广泛传播的腹泻性克隆相匹配。因为主要的克隆在遗传上是远距离相关的，并且表现出不同的毒力因子组合，所以我们假设它们具有不同的发病机理。结果表明，通过酶基因座的等位基因变异测量，细菌与O111抗原的遗传差异伴随克隆的毒力特性差异，因此致病性大肠杆菌菌株的鉴定和分类不能仅基于血清分型或单一毒力因子。

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