E.ColiO_(157):H_7的“VT”测定及致病性实验感染的研究

采用改良无铁酪蛋白水解物——酵母浸膏液作为产毒培养基,以多粘菌素 B(0.1mg/ml)处理菌体,再提取细菌滤液进行 vero 细胞毒素的测定;结果13株 E.ColiO_(157):H_7均能产生使 vero 细胞溶解、变性和死亡的 vero—toxin(VT)。运用实验小鼠,于腹部皮下注射1.2×10~8CFU/ml 活菌(0.3ml/只),于4～6h,小鼠即开始发病,其出现的症状及发病后各脏器的组织学改变,酷似人体发病后的表现,基本再现了出血性结肠炎和溶血性尿毒症综合征的疾病特征。

Determination of Vero-toxin from E.Coli O_(157):H_7 and the Pathogenicity of the Bacteria In Mice

The 13 isolated strains of E.CoLi O_(157):H_7were cul- tured in toxin-producing media containing casamino acid and yeast extract.The organisms were then treated with polymyx- in B(0.1mg/ml)to collect the filtrates for veto-toxin assay. It was found that the 13 strains all produced vero-toxin, which can cause lysis,degeneration and death of veto cells.A model was established in mice by injecting 1.2x10~8 CFU/ml living bacteria beneath the abdominal skin(0.3 ml each).The mice became ill 4-6 h later and their symptoms and visceral histopathoiogy were very similar to those in humans.The model replicated the characteristics of the disease in man,in- cluding hemorrhagic colitis and hemolytic uremic sybdrome.