An IncI1 plasmid contributes to the adherence of the atypical enteroaggregative Escherichia coli strain C1096 to cultured cells and abiotic surfaces
An IncI1 plasmid contributes to the adherence of the atypical enteroaggregative Escherichia coli strain C1096 to cultured cells and abiotic surfaces
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DOI：
10.1128/iai.74.4.2102-2114.2006
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发表时间：
2006-04-01
影响因子：
3.1
通讯作者：
Nataro, JP
中科院分区：
文献类型：
--
作者：
Dudley, EG;Abe, C;Nataro, JP
肠聚集性大肠埃希氏菌(EAEC)是一种典型的对培养细胞的“堆积式”聚集性黏附(AA)模式。在研究充分的EAEC原型株(称为典型EAEC株)中，AA表型需要聚集黏附菌毛(AAFS)。然而，先前的研究表明，并不是所有的EAEC菌株中都发现已知的AAF等位基因。为了确定非典型菌株的黏附机制，我们研究了EAEC菌株C1096。携带来自C1096的两个质粒(命名为pSERB1和pSERB2)的E.ColiK12衍生物附着在细胞系上，并呈现AA模式。PSERB1的核苷酸序列分析表明，它与IncI1不相容组的质粒群有关。这些质粒编码参与菌毛介导的配偶转移的基因，以及编码IV型家庭第二菌毛的Pill-V。预测编码主要IV型菌毛蛋白亚单位(PILS)的基因的插入失活使质粒的配偶转移减少了4个数量级。突变菌株对聚苯乙烯和HT29细胞的粘附率分别降低了约21%和75%。在连续流微生物发酵罐中，PILS的失活使玻片上成熟生物膜的形成减少了约50%。此外，pSERB1和pSERB2同时存在促进了PILS非依赖性生物膜的形成。我们的结论是，EAEC C1096的IncI1质粒编码一种IV型菌毛，该菌毛有助于质粒连接、上皮细胞黏附和非生物表面的黏附。我们还观察到，AA可以由不同于AAF粘附素的因素来调节。
Enteroaggregative Escherichia coli (EAEC) is defined by a characteristic "stacked-brick" aggregative adherence (AA) pattern to cultured cells. In well-studied EAEC prototype strains (called typical EAEC strains), the AA phenotype requires aggregative adherence fimbriae (AAFs). However, previous studies suggest that known AAF alleles are not found in all EAEC strains. To define mechanisms contributing to adherence in an atypical strain, we studied EAEC strain C1096. An E. coli K12 derivative carrying two plasmids, designated pSERB1 and pSERB2, from C1096 adhered to cell lines and exhibited an AA pattern. Nucleotide sequence analysis of pSERB1 indicated that it is related to plasmids of the IncI1 incompatibility group. These plasmids encode genes involved in pilus-mediated conjugal transfer, as well as pilL-V, which encodes a second pilus of the type IV family. Insertional inactivation of the gene predicted to encode the major type IV pilin subunit (pilS) reduced conjugal transfer of the plasmid by 4 orders of magnitude. Adherence of the mutant strain to polystyrene and to HT29 cells was reduced by approximately 21% and 75%, respectively. In a continuous-flow microfermentor, the pilS inactivation reduced mature biofilm formation on a glass slide by approximately 50%. In addition, the simultaneous presence of both pSERB1 and pSERB2 plasmids promoted pilS-independent biofilm formation. We conclude that the IncI1 plasmid of EAEC C1096 encodes a type IV pilus that contributes to plasmid conjugation, epithelial cell adherence, and adherence to abiotic surfaces. We also observe that AA can be mediated by factors distinct from AAF adhesins.