Identification of Coli Surface Antigen 23, a Novel Adhesin of Enterotoxigenic Escherichia coli
Identification of Coli Surface Antigen 23, a Novel Adhesin of Enterotoxigenic Escherichia coli
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DOI：
10.1128/iai.00263-12
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发表时间：
2012-08-01
影响因子：
3.1
通讯作者：
Vidal, Roberto
中科院分区：
文献类型：
--
作者：
Del Canto, Felipe;Botkin, Douglas J.;Vidal, Roberto
产肠毒素大肠埃希菌(ETEC)是引起腹泻的重要原因，主要发生在发展中国家。尽管在影响人类的菌株中描述了25种不同的ETEC粘附素，但来自不同地理地区的临床分离株中有15%至50%的粘附素呈阴性，这表明可能存在其他未知的黏附决定因素。在这里，我们报告发现了一种由ETEC血清组04菌株(ETEC 1766a)表达的新型粘附素--大肠杆菌表面抗原23(CS23)，该粘附素对先前已知的ETEC粘附素呈阴性反应，尽管它具有与Caco-2细胞黏附的能力。CS23由一个8.8kb的基因座编码，包含9个开放阅读框(ORF)，其中7个与K88相关菌毛组装所需的基因具有显著的同源性。该基因座命名为AAL(黏附相关基因座)，是ETEC 1766a黏附能力所必需的，并能够将这种黏附表型赋予非黏附的E.ColiHB101菌株。CS23主要结构亚基AALE与已知的菌毛蛋白有有限的同源性，与人ETEC携带的CS13菌毛蛋白CSHE关系更密切。我们的数据表明，CS23是ETEC菌株所使用的多种粘附素谱系中的一个新成员。
Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea, mainly in developing countries. Although there are 25 different ETEC adhesins described in strains affecting humans, between 15% and 50% of the clinical isolates from different geographical regions are negative for these adhesins, suggesting that additional unidentified adhesion determinants might be present. Here, we report the discovery of Coli Surface Antigen 23 (CS23), a novel adhesin expressed by an ETEC serogroup 04 strain (ETEC 1766a), which was negative for the previously known ETEC adhesins, albeit it has the ability to adhere to Caco-2 cells. CS23 is encoded by an 8.8-kb locus which contains 9 open reading frames (ORFs), 7 of them sharing significant identity with genes required for assembly of K88-related fimbriae. This gene locus, named aal (adhesion-associated locus), is required for the adhesion ability of ETEC 1766a and was able to confer this adhesive phenotype to a nonadherent E. coli HB101 strain. The CS23 major structural subunit, AalE, shares limited identity with known pilin proteins, and it is more closely related to the CS13 pilin protein CshE, carried by human ETEC strains. Our data indicate that CS23 is a new member of the diverse adhesin repertoire used by ETEC strains.