Unravelling Probiotic-Associated Traits and Protective Efficacy of Limosilactobacillus fermentum Strains Against Colitis.

Colitis is a serious gastrointestinal disorder, and drug therapy has problems of recurrence upon withdrawal as well as adverse effects from prolonged usage. Therefore, probiotics can be an effective substitute. This study aims to isolate bacterial strains having probiotic attributes and defensive traits against colitis. Initially, forty strains were isolated from Haria, a traditional rice-based fermented beverage of West Bengal, India. Eight isolates were selected based on their acid and bile salt tolerance properties. These selected isolates showed anti-amoebic activity against Entamoeba histolytica, a human protozoan parasite that causes colitis, amoebiasis and other disorders. Subsequently, the isolates were identified as Limosilactobacillus fermentum by 16S rRNA gene sequence analysis. Their phenotypic probiotic attributes, such as GI survival rate, good adhesion, antioxidant activity, inhibitory activity against four pathogenic bacterial strains, and safety evaluation, identified two promising strains, L-31 and L-35. They were further used as a probiotic mixture and ameliorated dextran sulfate sodium-induced colitis in experimental mice by protecting colon length and body weight loss, restoring organ indices, decreasing disease activity index score, improving blood parameters, reducing coliform count, and repairing tissues. L-31 has been identified as a promising candidate with good probiotic potential and protective effects against colitis, but further studies on its safety, efficacy, stability, formulation suitability, and clinical applicability are necessary for potential therapeutic applications.