Typing of intimin genes in human and animal enterohemorrhagic and enteropathogenic Escherichia coli:: Characterization of a new intimin variant
Typing of intimin genes in human and animal enterohemorrhagic and enteropathogenic Escherichia coli:: Characterization of a new intimin variant
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DOI：
10.1128/iai.68.11.6402-6410.2000
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发表时间：
2000-01-01
影响因子：
3.1
通讯作者：
Caprioli, A
中科院分区：
文献类型：
--
作者：
Oswald, E;Schmidt, H;Caprioli, A
肠致病性大肠杆菌 (EPEC) 和肠出血性大肠杆菌 (EHEC) 会产生刷状缘特征性的“附着和消失”(A/E) 病变。 Intimin 是一种由 eae 编码的外膜蛋白，负责两种病原体与宿主细胞的紧密结合。已从人类和动物分离的不同 EPEC 和 EHEC 菌株中克隆出几种 eae。这些序列在 N 端区域是保守的，但在最后的 C 端 280 个氨基酸 (aa) 中高度可变，细胞结合活性位于此处。基于这些考虑，我们开发了一组特异性引物，通过 PCR 扩增来研究可变 3' 区的烯异质性，然后我们研究了从人类和不同动物物种中分离的大量 EPEC 和 EHEC 菌株中已知 intimin 类型的分布。人们怀疑存在一个未知的 intimin 家族，因为从人和牛中分离出的几种肠出血性大肠杆菌菌株不与任何特定引物对发生反应，尽管当使用扩增保守 5' 末端的引物时，这些菌株呈 eae 阳性。然后，我们对这些菌株之一（血清型 O103:H2 的 EHEC）中存在的 ene 进行了克隆和测序，随后设计了一个 PCR 引物，该引物以特定方式识别这种新 intimin 类型的可变 3' 区。这种 intimin 被称为“epsilon”，存在于血清群 O8、O11、O45、O103、O121 和 O165 的人类和牛 EHEC 菌株中。 Intimin E 是迄今为止克隆的最大的 intimin (948 个氨基酸)，并且与 intimin beta 具有最大的总体序列同一性，尽管对最后一个 C 端 280 个氨基酸的分析表明与 intimin α 和 γ 具有更大的相似性。
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) produce the characteristic "attaching and effacing" (A/E) lesion of the brush border. Intimin, an outer membrane protein encoded by eae, is responsible for the tight association of both pathogens with the host cell. Several eae have been cloned from different EPEC and EHEC strains isolated from humans and animals. These sequences are conserved in the N-terminal region but highly variable in the last C-terminal 280 amino acids (aa), where the cell binding activity is localized. Based on these considerations, we developed a panel of specific primers to investigate the ene heterogeneity of the variable 3' region by using PCR amplification, We then investigated the distribution of the known intimin types in a large collection of EPEC and EHEC strains isolated from humans and different animal species. The existence of a yet-unknown family of intimin was suspected because several EHEC strains, isolated from human and cattle, did not react with any of the specific primer pairs, although these strains were eae positive when primers amplifying the conserved 5' end were used. We then cloned and sequenced the ene present in one of these strains (EHEC of serotype O103:H2) and subsequently designed a PCR primer that recognizes in a specific manner the variable 3' region of this new intimin type. This intimin, referred to as "epsilon," was present in human and bovine EHEC strains of serogroups O8, O11, O45, O103, O121, and O165. Intimin E is the largest intimin cloned to date (948 aa) and shares the greatest overall sequence identity with intimin beta, although analysis of the last C-terminal 280 aa suggests a greater similarity with intimins alpha and gamma.