Characterization of inhibitory factors of lactic acid bacteria against gastrointestinal pathogens

本研究的目的是阐明瑞氏乳杆菌和加瑟氏乳杆菌竞争性排除胃肠道病原体的能力。在前人研究的基础上，本研究首次确定了路氏乳杆菌JCM1081对硫脂糖链的黏附因子，该糖链被认为是幽门螺杆菌的受体部分。将潜在的黏附因子EF-Tu以重组蛋白的形式表达，并进行了动力学研究。该菌株的EF-Tu对硫脂具有较高的亲和力，在pH为4.0的条件下能紧密地附着在细胞表面，而在pH为6.0的条件下不能与之紧密结合。这一结果有力地表明EF-Tu是乳杆菌中一种新的硫脂糖链的黏附因子。空肠弯曲菌81-176感染雏鸡后，每天口服加氏乳杆菌TM333 7d，对空肠弯曲菌81-176的盲肠定植抑制率达98%。

The goal of our study was to elucidate the capacity of the Lactobacillus reuteri and Lactobacillus gasseri to competitively exclude gastrointestinal pathogens. On the basis of the previous results, this study was firstly conducted to determine the adhesion factor of L. reuteri JCM1081 to the sulfated sugar chains of sulfatide, which was recognized as a receptor moiety of Helicobacter pylori. The potential adhesion factor, Ef-Tu was expressed as a recombinant protein followed by kinetics studies. Ef-Tu of the strain was shown to be a high affinity for sulfatide and to be retained tightly on the cell surface at pH 4.0 but not to pH6.0.The findings strongly suggested that Ef-Tu is a novel adhesion factor the sulfated sugar chains of sulfatide to in Lactobacillus strains.Secondly, the capacity of fibronectin-adherent L. gasseri TM333 selected previously to competitively exclude Campylobacter jejuni 81-176 in chicks was examined. Chicks were given daily oral doses of L. gasseri TM333 for 7 days after oral infection with C. jejuni 81-176.The chicks treated with L. gasseri TM333 showed 98% inhibition of cecum colonization by C. jejuni 81-176.The findings indicate the fibronectin-adherent L. gasseri TM333 effectively inhibited Campylobacter colonization of the chick cecum.