Wray C, McLaren I, Pearson G R
Central Veterinary Laboratory, New Haw, Weybridge, Surrey.
Vet Rec. 1989 Sep 30;125(14):365-8. doi: 10.1136/vr.125.14.365.
Nine calves (five colostrum-fed, four colostrum-deprived) were challenged with two field strains of Escherichia coli which produced either verocytotoxin 1 (VT1) or verocytotoxin 2 (VT2). Although three colostrum-fed calves had blood and mucus in their faeces, no diarrhoea was observed. Three of the four colostrum-deprived calves had diarrhoea and in two of them severe lesions were detected in the small intestine. Focal changes were detected in the colon of three calves. E coli were associated with the lesions in the small and large intestine and were shown by transmission electron microscopy to be intimately attached to the enterocyte surface with effacement of microvilli (attaching and effacing lesions). This is the first report of E coli which produce VT2 being associated with disease in calves.
选用9头犊牛(5头初乳喂养,4头未喂初乳),用两株分别产生志贺毒素1(VT1)或志贺毒素2(VT2)的大肠杆菌田间菌株进行攻毒。尽管5头初乳喂养的犊牛中有3头粪便带血和黏液,但未观察到腹泻。4头未喂初乳的犊牛中有3头发病腹泻,其中2头在小肠发现严重病变。3头犊牛的结肠出现局灶性变化。大肠杆菌与小肠和大肠病变有关,透射电镜显示其紧密附着于肠上皮细胞表面,微绒毛消失(黏附性和剥脱性病变)。这是首次报道产VT2的大肠杆菌与犊牛疾病有关。