新疆牛源非O157 STEC菌株的致病性及其作用于HIEC细胞的机制研究

产志贺毒素大肠杆菌（STEC）是一类重要的食源性病原微生物，对人类身体健康具有重要的危害，牛是STEC的主要贮存宿主，新疆现代畜牧业发展的主导产业是牛羊养殖业，新疆褐牛粪便中存在一定数量的STEC，对牛肉质量安全存在潜在的危害。已有的研究集中在STEC O157:H7致病性和其志贺毒素在肠上皮细胞的胞吞饮作用机制，但目前非O157 STEC的发病率越来越高。本项目拟以新疆褐牛粪便中分离鉴定的非O157 STEC菌株为研究对象，通过致病性试验、细胞感染模型、志贺毒素作用机制等研究，明确该菌株的致病能力，揭示其感染人正常肠上皮细胞（HIEC）的数量、结构和形态变化，验证志贺毒素（stx1、stx1A、stx1B）与HIEC的作用机制。研究结果不仅揭示新疆分离株非O157 STEC的致病性，并为爆发非O157 STEC食源性疾病方面提供理论依据，还可为预防和治疗STEC疾病方面提高科学理论资料。

Shiga toxin-producing Escherichia coli is an important food borne pathogenic microorganism, which is harmful to human health. The cattle is the main storage host of STEC. The cattle and sheep of breeding industry is the leading industry in the development of modern animal husbandry in Xinjiang, there was a certain amount of STEC in the feces of the Xinjiang brown cattle, which has potential harm to the quality and safety of beef. Previous studies have focused on the pathogenesis of STEC O157:H7 and the mechanism of macropinocytosis of STEC O157:H7 with Shiga toxin in intestinal epithelial cells, but the incidence of non O157 type STEC is increasing in nowadays. This project is based on the identification of non O157 STEC strains isolated from feces of Xinjiang brown cattle, by study the pathogenicity of the strain, cell infection model, Shiga toxin of action mechanism. To define the pathogenicity of strain, to reveal the infection of human intestinal epithelial cells of the number, structure and morphology, to verify the action mechanism of Shiga toxin (stx1, stx1A and stx1B) and HIEC. The results not only reveal the pathogenicity of non O157 STEC isolated from Xinjiang, but also provide the theoretical basis for the outbreak of non O157 STEC foodborne diseases, and also can improve the scientific data for the prevention and treatment of STEC disease.