尿路致病性大肠埃希菌(uropathogenic Escherichia coli, UPEC) 是尿路感染最常见的病原菌。 UPEC表达多种毒力因子，使细菌能在宿主泌尿道持续生长和繁殖，引起炎症反应和组织破坏。其中黏附因子是最主要的一类毒力因子，包括1型、P型、S型、FIC型菌毛及Afa/Dr黏附因子家族等。泌尿道上皮细胞中存在各种黏附因子受体，黏附因子通过与这些受体结合，使细菌黏附于泌尿道上皮细胞，部分还可直接参与UPEC入侵上皮细胞，帮助UPEC在宿主细胞内繁殖，形成胞内生物膜样菌落，逃避宿主免疫系统攻击，减弱对外来抗菌药物的敏感性，并形成细菌贮存库，造成尿路感染反复发作。

Strains of uropathogenic Escherichia coli (UPEC) are the most common pathogens of urinary tract infection. These bacteria exhibit a multitude of virulence factors to facilitate bacterial growth and persistence within the urinary tract and evoke inflammatory reactions and tissue destruction. Among those virulence factors , adhesive factors including type l, P, S and FIC fimbriae (pili) and Afa/Dr family of adhesins play a prominent role in mediating bacterial attachment to and invasion of host uroepithelial cells, by recognizing the matched receptors allocated there. Some adhesins even promote the formation of intracellular bacterial communities and quiescent intracellular reservoir, and therefore not only weaken innate immune responses and antibiotic applications but cause recurrent episodes of urinary tract infection also.