Département de Biologie, Faculté des Sciences, Centre d'Etude et de Valorisation de la Diversité Microbienne (CEVDM), Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Foodborne Pathog Dis. 2010 Aug;7(8):985-90. doi: 10.1089/fpd.2009.0474.
Reports show that sorbitol-fermenting (SF) Escherichia coli O157 isolates are implicated in animal and human diseases and may represent new emerging pathogens. We investigated the cytotoxicity and interaction with intestinal tissues of an SF, Shiga-toxin-negative E. coli O157:NM isolate. This bovine isolate was negative for stx genes and was not cytotoxic for Vero cells. We found that this E. coli O157 isolate possesses an intimin of type beta, whereas the translocated intimin receptor Tir and type III secretion system components EspA, EspB, and EspD were of type alpha. In contrast, Shiga-toxin-positive O157:H7 isolates usually possess variants of type gamma. The isolate did not present typical O157:H7 attaching and effacing lesions in the newborn pig ileal in vitro organ culture model. However, extensive effacement and elongation of the microvilli were observed. In vitro organ culture results suggest that such an SF, Shiga-toxin-negative O157:NM isolate found in cattle may potentially cause disease, such as diarrhea without hemolytic uremic syndrome, in humans.
报告显示，山梨糖醇发酵（SF）大肠杆菌 O157 分离株与动物和人类疾病有关，可能代表新出现的病原体。我们研究了一种 SF、产志贺毒素阴性大肠杆菌 O157：NM 分离株的细胞毒性及其与肠道组织的相互作用。该牛分离株 stx 基因阴性，对 Vero 细胞无细胞毒性。我们发现，这种大肠杆菌 O157 分离株具有β型内膜蛋白，而转位内膜蛋白受体 Tir 和 III 型分泌系统成分 EspA、EspB 和 EspD 则为α型。相比之下，产志贺毒素阳性 O157:H7 分离株通常具有γ型变体。该分离株在新生仔猪回肠体外器官培养模型中未呈现典型的 O157:H7 黏附和消除病变。然而，观察到微绒毛广泛的消失和伸长。体外器官培养结果表明，在牛中发现的这种 SF、产志贺毒素阴性 O157：NM 分离株可能在人类中引起疾病，例如无溶血性尿毒症综合征的腹泻。
