Interaction between putative probiotic Lactobacillus strains of Indian gut origin and Salmonella: Impact on intestinal barrier function

摘要

A total of 35 strains of putative probiotic Lactobacilli of Indian gut origin were screened for antimicrobial activity against Salmonella enterica subspecies enterica serovar Typhi Ty2 (S. Typhi Ty2) and Salmonella enterica subspecies enterica serovar Typhimurium LT2 (S. Typhimurium LT2). Eleven strains exhibiting moderate to a high antagonistic activity were further analysed for their cell surface properties and adhesion interference activity against Salmonella infection on HT-29 cells. Lactobacillus strains MTCC 5690, LrhS3, Lp9, Lp4 and Lr120 turned out to be the most effective against inhibition of Salmonella attachment and invasion as they possessed good cell surface properties. However, the capability to influence the transcriptional expression level of barrier function components (MUC2, tight junction proteins) in S. Typhi Ty2 treated HT-29 varied with strains. Besides, most of the putative probiotic strains under investigation suppressed the relative expression of TLR4 gene under the same treatment conditions. The findings revealed that the probiotic strains improved the intestinal barrier function through TLR2 and TLR4 mediated mechanism. Furthermore, our observations suggest that the cell surface properties may influence the anti-Salmonella efficacy of probiotics, by manipulating the attachment and cross talk between probiotic bacteria and gut epithelial cells. (C) 2016 Published by Elsevier Ltd.