本世纪德国大规模爆发的肠出血性大肠杆菌感染事件，涉及到全球14个国家。医生从未见过如此厉害的大肠杆菌，一时感到束手无策，更头疼的是病菌的源头迟迟查不出来，使得无法采取有效措施。因此，病原性微生物的污染而引起的食品不安全的问题，不但没有因为科技发展而日渐改观，形势反而变得更加严峻，严重威胁着人类健康。本项目立足于地区资源优势和前期研究，在全面进行牛源肠道病原性大肠杆菌特征的鉴定基础上，建立牛源病原性大肠杆菌信息库。明确地区病原性大肠杆菌不同生长期的毒性、血清型、致病性和毒力基因特征。研究鉴定病原菌的不同生长期对宿主免疫机能、肠道形态结构、肠黏膜免疫细胞和Peyer's结分泌因子的影响规律。从细胞、分子水平上揭示病原性大肠杆菌的危害性。研究酸马奶活性物和厩螫蝇抗菌肽对肠道病原性大肠杆菌的细胞表面特性影响及其作用机理。实现减少病原性大肠杆菌排放问题，为牛业健康持续发展提供理论依据。

German large-scale outbreak of EHEC infection event involved 14 countries around the world. The doctors have never touched so terrible E. coli strains, and sometimes felt helpless. More headaches are that the source of the bacteria is uneasy to be checked out, which makes it impossible to take effective measures to prevent them. Therefore, food insecurity problems induced by pathogenic microbial contamination are not resolved because of the development of science and technology, however, are becoming even more severe and are a threat to human health. Based on the regional resource advantages and preliminary studies, and on the comprehensive identification of bovine intestinal pathogenic E. coli characteristics, the current project will establish up an information library for bovine pathogenic E. coli strains; to clarify the distinctions for the toxicity, serotype, pathogenicity and virulence genes characteristics of regional pathogenic E. coli between the different growth phases; to illustrate the law for the effect of pathogens at different growth phases on host immune function, intestinal morphology, immune cells of the intestinal mucosa and secretary factors of Peyer's node. In addition, the effect of koumiss actives and Stomoxys calcitrans antimicrobial peptides on the cell surface characteristics of intestinal pathogenic E. coli and its mechanism of action will be tested. These studies will reveal the dangers of pathogenic E. coli on the cellular and molecular level, and will enforce the reduction of pathogenic E. coli emissions and provide a theoretical study for the healthy and sustainable development of the cattle industry.