Lactobacillus gasseri relieves diarrhea caused by enterotoxin-producing Escherichia coli through inflammation modulation and gut microbiota regulation

Abstract

Lactobacillus gasseri can alleviate diarrhea caused by enterotoxin-producing Escherichia coli (ETEC) which is the main cause of traveler's diarrhea. There have been limited studies conducted using Lactobacillus gasseri as a treatment for diarrhea caused by ETEC. Additionally, the mechanisms for Lactobacillus gasseri alleviating ETEC-induced diarrhea show variation. In the present study, we compared the alleviating effects of five strains of Lactobacillus gasseri on diarrhea caused by ETEC and investigated their possible mechanisms. The results showed that L. gasseri QJSWX309M31, FGSYC9L1, and FSDHZ3L5 could relieve diarrhea due to ETEC infection. Infection of ETEC led to an increase in inflammatory cytokines including interferon-γ (IFN-γ), tumor necrosis factor (TNF-α), and interferon (IL)-6, which could be significantly decreased by both L. gasseri QJSWX309M31 and FGSYC9L1. Moreover, L. gasseri QJSWX309M31, FGSYC9L1, and FFJND4L5 could decrease the heat-stable enterotoxin (ST). In addition, gut microbiota was dramatically imbalanced by ETEC infection, including an increase in Escherichia-Shigella and Akkermansia, and a decrease in Coriobacteriaceae UCG-002, Ruminiclostridium 5, Lactobacillus, Lachnoclostridium, Citrobacter, Clostridioides and Blautia, and gavage of L. gasseri resulted in a significant recovery of gut microbiota. Furthermore, FGSYC9L1 and QJSWX309M31 could significantly increase acetic acid and propionic acid, while FSDHZ3L5, FFJND4L5, and QJSWX116L3 up-regulated propionic acid. In summary, L. gasseri FGSYC9L1 alleviated diarrhea caused by ETEC by alleviating jejunal damage, reducing inflammatory factors, normalization of gut microbiota, and producing short-chain fatty acids (SCFAs), which has fundamental implications for future product development and related basic research.