Mitigating Enterotoxigenic Escherichia coli (ETEC) infection with Probiotic and Synbiotic Treatments: A murine and in vitro study

Background & AimsEnterotoxigenic Escherichia coli (ETEC) strain H10407 is a major causative agent of Diarrhoeal diseases. This study investigates the inhibitory effects of selected probiotics (Lactobacillus casei, Lactococcus lactis, and Bifidobacterium bifidum) and their synbiotic combinations with inulin on ETEC proliferation, adhesion, intestinal colonization, and host immune response. MethodsETEC H10407 was cultured in Luria-Bertani broth and co-cultured with probiotic strains to assess growth dynamics. Adhesion and competitive inhibition assays were performed using INT 407 intestinal epithelial cells. A murine infection model (C57BL/6) was employed to evaluate pathogen colonization, diarrheal severity, stool consistency, histopathological changes, and immune modulation. Synbiotic efficacy was further tested by combining probiotics with the prebiotic inulin. Additionally, fecal microbiota transfer (FMT) was conducted to examine microbiome-mediated protective effects. ResultsProbiotic co-culture significantly inhibited ETEC growth from 2 h onward without impairing probiotic viability. All probiotics markedly reduced ETEC adhesion to INT 407 small intestinal cells. In vivo, probiotics lowered ETEC colonization by 81.34%, while synbiotics conferred an additional 29.68% reduction. Synbiotics prevent watery stool and preserve ileal architecture, with reduced goblet cell loss and neutrophil infiltration. Synbiotics significantly (p<0.0001) decreased CD3+/CD4+ Th1 cells in spleen and mesenteric lymph nodes, reduced pro-inflammatory cytokines and chemokines, and restored tight junctional proteins. ConclusionSynbiotic supplementation offered superior protection against ETEC-induced diarrhea compared to probiotics or prebiotics alone, highlighting its potential as a non-antibiotic prophylactic strategy. These findings support the role of microbiome-targeted interventions within the One Health framework to address enteric infections and antimicrobial resistance.