Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and three (O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.

中文翻译：

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大肠杆菌 O 抗原的结构和遗传学


大肠杆菌包括共生菌株和致病菌株的克隆群，其中一些致病菌株会引起严重的传染病。 O 抗原变异是当前分类学和流行病学菌株定义的标准，为革兰氏阴性菌的许多血清分型方案提供了基础。本综述涵盖了大肠杆菌O 抗原结构和基因簇的多样性，以及结构多样性的遗传基础。在 187 种正式定义的 O 抗原中，六种（O31、O47、O67、O72、O94 和 O122）已被删除，三种（O34、O89 和 O144）菌株不产生任何 O 抗原。因此，给出了 181 种大肠杆菌O 抗原中 176 种的结构，其中一些包括亚组。大多数（93%）这些 O 抗原是通过 Wzx/Wzy 途径合成的，其中 11 个是通过 ABC 转运蛋白途径合成的，其中 O20、O57 和 O60 由于未能找到其 O 抗原基因簇而仍未被表征。给出了大肠杆菌O 抗原中发现的 49 种糖中的 38 种的生物合成途径，并且具有相关结构的几对或几组大肠杆菌抗原显示了进化枝内 O 抗原基因簇的密切关系，从而突出了遗传基础多样性的演变。