College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.
Vet Microbiol. 2013 Sep 27;166(1-2):220-4. doi: 10.1016/j.vetmic.2013.04.030. Epub 2013 May 22.
Flagellar structures contribute to the virulence of multiple gastrointestinal pathogens either as the effectors of motility, as adhesins, or as a secretion apparatus for virulence factors. Escherichia coli F18ab variant strains are associated with edema disease (ED) in pig industries worldwide. These strains use flagella to increase the efficiency of epithelial cell invasion. In this study, we aimed to elucidate the mechanism by which flagella contribute to F18ab E. coli invasion. To explore the role of flagella in the invasion process, we performed invasion assays with either flagellated and motile, flagellated but non-motile, or non-flagellated non-motile bacteria. We observed that flagellated but non-motile bacteria invade piglet epithelial cells even more efficiently than the parent wild-type (WT) strain in vitro. By contrast, the non-flagellated bacteria have significantly reduced invasion as compared with the parent strain. These results demonstrate that flagella function mainly as adhesins to enhance the ability of F18ab E. coli to target piglet epithelial cells.
鞭毛结构作为运动效应器、黏附素或毒力因子分泌装置，有助于多种胃肠道病原体的毒力。全球范围内，猪产业中的大肠杆菌 F18ab 变异株与水肿病（ED）相关。这些菌株利用鞭毛提高上皮细胞侵袭的效率。在本研究中，我们旨在阐明鞭毛有助于 F18ab 大肠杆菌侵袭的机制。为了探究鞭毛在侵袭过程中的作用，我们用有鞭毛且运动的、有鞭毛但不运动的或无鞭毛且不运动的细菌进行侵袭实验。我们发现，体外实验中，有鞭毛但不运动的细菌比亲本野生型（WT）菌株更有效地侵袭仔猪上皮细胞。相比之下，无鞭毛细菌的侵袭能力与亲本菌株相比显著降低。这些结果表明，鞭毛主要作为黏附素发挥作用，增强 F18ab 大肠杆菌靶向仔猪上皮细胞的能力。
