Moxley R A, Francis D H
Infect Immun. 1986 Aug;53(2):339-46. doi: 10.1128/iai.53.2.339-346.1986.
Gnotobiotic calves were inoculated with an O5:K4:H-, urease-positive strain of Escherichia coli isolated from a 2-day-old calf with diarrhea. The calves developed elevated temperatures and passed loose mucoid feces, with or without blood. The E. coli strain was negative for heat-stable and heat-labile enterotoxins but produced high levels of Shiga-like toxin. Bacteria attached diffusely to the epithelium of the large intestine and multifocally to the epithelium of the ileum. The duodenum and jejunum were not affected. At the sites of bacterial attachment, microvilli were effaced, enterocytes were degenerate, and necrosis and exfoliation had occurred. These results confirm a previous report from England that calves may naturally contract infections similar to those caused by enteropathogenic E. coli strains pathogenic to humans or rabbits. This suggests that the calf bacterial strains, like some enteropathogenic E. coli strains, produce high levels of Shiga-like toxin and cause attachment and effacement lesions in the colonic epithelium of the infected host.
将无菌小牛接种从一头患腹泻的2日龄小牛分离出的O5:K4:H-、脲酶阳性大肠杆菌菌株。小牛体温升高，排出带或不带血液的稀软黏液便。该大肠杆菌菌株的耐热和不耐热肠毒素均为阴性，但产生高水平的志贺样毒素。细菌广泛附着于大肠上皮，多处附着于回肠上皮。十二指肠和空肠未受影响。在细菌附着部位，微绒毛消失，肠上皮细胞变性，出现坏死和脱落。这些结果证实了英国之前的一份报告，即小牛可能自然感染类似于由对人类或兔子致病的肠致病性大肠杆菌菌株所引起的感染。这表明小牛的细菌菌株，像一些肠致病性大肠杆菌菌株一样，产生高水平的志贺样毒素，并在受感染宿主的结肠上皮中引起附着和脱落性病变。
