Bacillus velezensis HBXN2020 alleviates Salmonella Typhimurium-induced colitis by improving intestinal barrier integrity and reducing inflammation

Abstract

Bacillus velezensis is a novel species of Bacillus that has been widely investigated because of its broad-spectrum antimicrobial activity. However, most studies on Bacillus velezensis have focused on biocontrol of plant diseases, with few reports on antagonizing Salmonella Typhimurium infections. In this study, Bacillus velezensis HBXN2020 was isolated from healthy black piglets and was found to exhibit broad-spectrum antibacterial activity and robust anti-stress capabilities. Importantly, Bacillus velezensis HBXN2020 did not cause any adverse side effects in mice when administered at various doses (1 × 10 7 , 1 × 10 8 , and 1 × 10 9 CFU) for 14 days. In a Salmonella Typhimurium ATCC14028-induced mice colitis model, either curative or prophylactic, supplementing Bacillus velezensis HBXN2020 spores significantly lowered the levels of Salmonella Typhimurium ATCC14028 in their feces, ileum, cecum, and colon, and the disease activity index (DAI). Importantly, supplementing Bacillus velezensis HBXN2020 spores significantly regulated cytokine levels (TNF-α, IL-1β, IL-6, and IL-10) and maintained the expression of tight junction proteins and mucin protein. More importantly, supplementing Bacillus velezensis HBXN2020 spores also significantly enhanced the homeostasis of colonic microbiota and the abundance of beneficial bacteria. Collectively, Bacillus velezensis HBXN2020 can alleviate bacterial colitis by enhancing intestinal homeostasis and gut barrier integrity and reducing inflammation.