Bacillus subtilis SF106 and Bacillus clausii SF174 spores reduce the inflammation and modulate the gut microbiota in a colitis model

Abstract Chronic intestinal inflammation is associated with strong alterations of the microbial composition of the gut. Probiotic treatments and microbiota-targeting approaches have been considered to reduce the inflammation, improve both gut barrier function as well as overall gastrointestinal health. Here, a murine model of experimental colitis was used to assess the beneficial health effects of Bacillus subtilis SF106 and Bacillus clausii (recently renamed Shouchella clausii ) SF174, two spore-forming strains previously characterised in vitro as potential probiotics. Experimental colitis was induced in BALB/c mice by the oral administration of dextran sodium sulphate (DSS) and groups of animals treated with spores of either strain. Spores of both strains reduced the DSS-induced inflammation with spores of B. clausii SF174 more effective than B. subtilis SF106. Spores of both strains remodelled the mouse gut microbiota favouring the presence of beneficial microbes such as members of the Bacteroidetes and Akkermansia genera.