Sears C L, Myers L L, Lazenby A, Van Tassell R L
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA.
Clin Infect Dis. 1995 Jun;20 Suppl 2:S142-8. doi: 10.1093/clinids/20.supplement_2.s142.
Enterotoxigenic Bacteroides fragilis (ETBF) has been recently associated with watery diarrheal disease in livestock and young children. These strains of B. fragilis secrete an extracellular heat-labile protein toxin with a mess of approximately 20 kD. This toxin has been shown to have two major biological activities: stimulation of secretion in ligated intestinal segments in lambs and calves and alteration of the morphology of intestinal epithelial cell lines in vitro. In vivo the pathology of animal intestine exposed to an ETBF strain is disruption of the colonic epithelium with rounded, swollen surface epithelial cells. Similarly, in vitro intestinal epithelial cells derived from human colonic carcinomas become rounded and detach from neighboring cells after treatment with the ETBF toxin. These results suggest that the ETBF toxin is a secretory cytoskeleton-altering toxin. However, the contribution of the ETBF toxin to the pathogenesis of ETBF-associated diarrheal disease remains to be determined.
产肠毒素脆弱拟杆菌（ETBF）最近被认为与家畜和幼儿的水样腹泻病有关。这些脆弱拟杆菌菌株分泌一种细胞外热不稳定蛋白毒素，分子量约为20 kDa。已证明这种毒素具有两种主要生物学活性：刺激羔羊和犊牛结扎肠段的分泌，以及在体外改变肠上皮细胞系的形态。在体内，暴露于ETBF菌株的动物肠道病理表现为结肠上皮破坏，表面上皮细胞呈圆形、肿胀。同样，在体外，源自人结肠癌的肠上皮细胞在用ETBF毒素处理后会变圆并与相邻细胞分离。这些结果表明，ETBF毒素是一种改变分泌性细胞骨架的毒素。然而，ETBF毒素对ETBF相关腹泻病发病机制的作用仍有待确定。
