New adhesin of enteroaggregative Escherichia coli related to the Afa/Dr/AAF family
New adhesin of enteroaggregative Escherichia coli related to the Afa/Dr/AAF family
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DOI：
10.1128/iai.01646-07
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发表时间：
2008-07-01
影响因子：
3.1
通讯作者：
Nataro, James P.
中科院分区：
文献类型：
--
作者：
Boisen, Nadia;Struve, Carsten;Nataro, James P.
肠聚集性大肠杆菌（EAEC）是引起腹泻的重要原因。我们分析了17丹麦EAEC菌株，在病例对照研究过程中分离，表型和基因型特性。菌株属于至少14种不同的血清型。使用PCR来调查各种推定的毒力基因的患病率，我们发现，所有，但两个菌株是典型的EAEC，因为他们窝藏全部或部分先前描述的AggR调节子。大多数菌株携带编码聚集粘附菌毛（AAF）的基因。最常见的是AAF/I，在9个菌株中发现; 8个菌株没有已知的AAF相关基因。我们利用TnphoA诱变定位聚集粘附（AA）粘附素从一个典型的EAEC株，C1010-00，它缺乏一个已知的AAF。我们确定了一个TnphoA插入一个假设的博士相关的菌毛蛋白存放在基因库作为HdaA。另外四个丹麦菌株窝藏HdaA，和所有，但一个显示AA HEp-2细胞。通过使用来自三个AAF和Hda的菌毛蛋白和引座蛋白的PCR引物，我们发现17株中有16株表现出这些因素之一的证据;重要的是，一个阴性菌株也缺乏aggR基因。Hda基因簇的克隆及在大肠杆菌中的表达coliDH 5 α诱导C1010-00非贴壁突变体产生AA和互补。现在已经发现四个相关的粘附素赋予AA在典型的EAEC菌株，我们的数据表明，在一起，这些变体可能占AA在绝大多数菌株。
Enteroaggregative Escherichia coli (EAEC) is an important cause of diarrhea worldwide. We analyzed 17 Danish EAEC strains, isolated in the course of a case control study, for phenotypic and genotypic properties. The strains belonged to at least 14 different serotypes. Using PCR to investigate the prevalence of various putative virulence genes, we found that all but two strains were typical EAEC, as they harbored all or part of the previously described AggR regulon. The majority of the strains harbored genes encoding aggregative adherence fimbriae (AAF). The most common was AAF/I, found in nine strains; eight strains carried no known AAF-related genes. We utilized TnphoA mutagenesis to localize the aggregative adherence (AA) adhesin from one typical EAEC strain, C1010-00, which lacked a known AAF. We identified a TnphoA insertion in a hypothetical Dr-related pilin deposited in GenBank as HdaA. Four additional Danish strains harbored HdaA, and all but one displayed AA to HEp-2 cells. By using PCR primers derived from the pilins and ushers from the three AAF and Hda, we found that 16 of 17 strains exhibited evidence of one of these factors; importantly, the one negative strain also lacked the aggR gene. Cloning of the complete Hda gene cluster and expression in E. coli DH5 alpha resulted in AA and complementation of the C1010-00 nonadherent mutant. Four related adhesins have now been found to confer AA in typical EAEC strains; our data suggest that, together, these variants may account for AA in the large majority of strains.