Molecular Characterization Reveals Three Distinct Clonal Groups among Clinical Shiga Toxin-Producing Escherichia coli Strains of Serogroup O103
Molecular Characterization Reveals Three Distinct Clonal Groups among Clinical Shiga Toxin-Producing Escherichia coli Strains of Serogroup O103
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DOI：
10.1128/jcm.00789-12
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发表时间：
2012-09-01
影响因子：
9.4
通讯作者：
Ohnishi, Makoto
中科院分区：
文献类型：
--
作者：
Iguchi, Atsushi;Iyoda, Sunao;Ohnishi, Makoto
产滋贺毒素大肠杆菌（STEC）是最重要的食源性致病菌之一，属于血清型O 103：H2的STEC菌株可引起人类腹泻、出血性结肠炎和溶血性尿毒症综合征。STEC O 103：非H2菌株有时也从人类患者中分离出来，但其遗传特征和在重大人类肠道疾病中的作用尚不清楚。在此，我们调查了17株STEC O 103：non-H2菌株，包括O 103：H11、O 103：H25、O 103：HUT（UT [untypeable]）和O 103：H-（nonmotile），并将其特征与STEC O 103：H2和其他血清型STEC菌株进行了比较。fliC和eae基因的序列分析显示，菌株具有以下任何组合：fliC-H2/eae-β 1、fliC-H11/eae-β 1和fliC-H25/eae-θ，其中fliC-H2、-H11和-H25分别表示编码H2、H11和H25鞭毛抗原的fliC基因，eae-β 1和-θ分别表示编码鞭毛抗原、β 1和θ亚类的eae基因。基于7个管家基因序列的系统发育分析表明，O 103：H11/[fliC-H11]和O 103：H25/[fliC-H25]菌株形成了两个不同的群体，与O 103：H2/[fliC-H2]菌株不同。有趣的是，由O 103：H11菌株组成的组与STEC O26：H11密切相关，STEC O26：H11被认为是最重要的非O 157血清型，这表明STEC O 103：H11和STEC O26：H11克隆从共同的祖先进化而来。本研究中描述的用于STEC O 103菌株快速分型的多重PCR系统可能有助于STEC O 103：H2、O 103：H11和O 103：H25组的临床和流行病学研究。此外，我们的数据提供了对STEC菌株的高变异性与新兴的新血清型的进一步见解。
Shiga toxin-producing Escherichia coli (STEC) is one of the most important groups of food-borne pathogens, and STEC strains belonging to the serotype O103:H2 can cause diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome in humans. STEC O103:non-H2 strains are also sometimes isolated from human patients, but their genetic characteristics and role in significant human enteric disease are not yet understood. Here, we investigated 17 STEC O103:non-H2 strains, including O103:H11, O103:H25, O103:HUT (UT [untypeable]), and O103:H- (nonmotile) isolated in Japan, and their characteristics were compared to those of STEC O103:H2 and other serotype STEC strains. Sequence analyses of fliC and eae genes revealed that strains possessed any of the following combinations:fliC-H2/eae-epsilon, fliC-H11/eae-beta1, and fliC-H25/eae-theta, where fliC-H2, -H11, and -H25 indicate fliC genes encoding H2, H11, and H25 flagella antigens, respectively, and eae-epsilon, -beta1, and -theta indicate eae genes encoding epsilon, beta1, and theta subclass intimins, respectively. Phylogenetic analysis based on the sequences of seven housekeeping genes demonstrated that the O103:H11/[fliC-H11] and O103:H25/[fliC-H25] strains formed two distinct groups, different from that of the O103:H2/[fliC-H2] strains. Interestingly, a group consisting of O103:H11 strains was closely related to STEC O26:H11, which is recognized as a most important non-O157 serotype, suggesting that the STEC O103:H11 and STEC O26:H11 clones evolved from a common ancestor. The multiplex PCR system for the rapid typing of STEC O103 strains described in the present study may aid clinical and epidemiological studies of the STEC O103:H2, O103:H11, and O103:H25 groups. In addition, our data provide further insights into the high variability of STEC stains with emerging new serotypes.