产肠毒大肠杆菌是导致细菌性腹泻的主要病原菌。由于抗生素的滥用导致ETEC的耐药性问题日趋严峻。利用乳酸菌来预防或辅助治疗ETEC的感染是学界普遍认可的安全有效的途径。但基于哺乳动物模型肠道菌群的复杂性、临床数据干扰多、动物世代周期长的局限，体外模型和体内实验结果缺乏高置信度关联的制约，致使乳酸菌干预ETEC感染的分子机制迄今仍不明晰。秀丽隐杆线虫具有肠道简单、免疫系统高度保守等特点，已成为现今研究微生物与宿主相互作用的理想模式生物。本课题在前期筛出具有抗ETEC活性的植物乳酸菌的基础上，拟将进一步从免疫调控、信号转导等领域入手，采用基因敲除、基因沉默、RT-PCR、Western blot等手段，研究植物乳酸菌通过线虫的信号通路及下游免疫途径干预ETEC感染的机理。研究结果将有助于全面认识益生乳酸菌在抗ETEC感染中发挥有益作用的分子机制，为功能性乳酸菌的开发提供理论依据和新的思路。

Enterotoxigenic Escherichia coli (ETEC) is a major pathogen causing diarrhea. There is a growing concern over the practice due to the wide spread of antibiotic-resistance in zoonotic bacterial pathogens, which poses a threat to public health. Thus, control strategies of the pathogen by lactic acid bacteria is acknowledged to be a potential alternative to antibiotics.The mechanism of lactic acid bacteria against ETEC is still not clear because of the complexity of mammalian models of intestinal flora, clinical interference, animal generation cycle length, different result in vitro with in vivo experiments. Caenorhabditis elegans is an ideal model for host and bacteria researches with its simple, highly conserved features used to underline the effect of Lactobacillus against ETEC and regulation on C. elegans immune signal pathways by using RT-PCR, fluorescence-labeled nematodes, gene silencing (iRNA), gene- knockout nematodes and western blot basing on previous results. The present study will not only helping for understanding the mechanism of Lactobacillus against ETEC, but also provided the theoretical foundation and scientific evidence for development of functional food of Lactobacillus.