Pawłowska Barbara, Sobieszczańska Beata M
Department of Microbiology, Wroclaw Medical University, Poland.
Adv Clin Exp Med. 2017 Dec;26(9):1437-1445. doi: 10.17219/acem/64883.
Diarrheagenic Escherichia coli strains are included in 9 pathotypes (pathovars) that present different virulence factors responsible for the patomechanism of infections they cause. As all other intestinal pathogens, E. coli exerts a significant effect on intestinal epithelium. To initiate the infection, these microorganisms have evolved countless strategies to subvert the epithelial barrier and efficiently colonize the intestinal epithelium. The barrier function of the intestinal epithelium is achieved by the presence of a tight junction protein network surrounding individual cells around their circumference that links neighboring cells and seals the intracellular space. Pathogenic E. coli strains may impair intestinal epithelial barrier in 3 different pathways: (i) through a direct effect of their virulence factors on tight junctions proteins, (ii) by disrupting host cell actin cytoskeleton that indirectly damages epithelial barrier, and (iii) via stimulation of the secretion of proinflammatory cytokines that directly disrupt epithelial tight junctions or trigger neutrophils migration through intestinal epithelium, thus disrupting the intestinal barrier. Most pathogenic E. coli generates all these 3 pathways concomitantly upon interaction with intestinal epithelium.
致泻性大肠杆菌菌株包含在9种致病型（致病变种）中，这些致病型具有不同的毒力因子，这些毒力因子是它们所引起感染的发病机制的原因。与所有其他肠道病原体一样，大肠杆菌对肠道上皮有显著影响。为了引发感染，这些微生物已经进化出无数策略来破坏上皮屏障并有效地定殖于肠道上皮。肠道上皮的屏障功能是通过围绕单个细胞周围的紧密连接蛋白网络来实现的，该网络连接相邻细胞并封闭细胞内空间。致病性大肠杆菌菌株可能通过3种不同途径损害肠道上皮屏障：（i）通过其毒力因子对紧密连接蛋白的直接作用，（ii）通过破坏宿主细胞肌动蛋白细胞骨架间接损害上皮屏障，以及（iii）通过刺激促炎细胞因子的分泌，直接破坏上皮紧密连接或触发中性粒细胞通过肠道上皮迁移，从而破坏肠道屏障。大多数致病性大肠杆菌在与肠道上皮相互作用时会同时产生这3种途径。
