Bacteriocin bifidocin A from Bifidobacterium animalis subsp. animalis BB04 alleviate Listeria monocytogenes-induced intestinal infection in vitro and in vivo.

Intestinal infection induced by foodborne pathogens poses a significant threat to human health. Bifidocin A, a novel bacteriocin derived from the first reported bacteriocin-producing strain Bifidobacterium animalis subsp. animalis BB04, and exhibits a broad-spectrum antibacterial activity against foodborne pathogen. This study aimed to investigate the improvement effect and the underlying molecular mechanism of bifidocin A on the intestinal infection induced by Listeria monocytogenes, focusing on the gut barrier, gut inflammation, and gut microbiota. The results indicated that bifidocin A showed antibacterial activity against enteric pathogenic bacteria, exhibited the improvement effects against L. monocytogenes-induced Caco-2 cell damage. Bifidocin A, especially at high doses (HB, 8 MIC, 185.6 μg), showed considerable promise effect by inhibiting the activation of MAPK/NF-κB signaling pathway alleviating gut inflammation, upregulating expressions of tight junction-associated protein, and enhancing host defense against gut inflammation and gut barrier damage. Additionally, bifidocin A contributes to restoring gut microbial balance by increasing its diversity and enhancing beneficial bacteria abundance. This further elevated the short-chain fatty acids, reduced the lipopolysaccharides, and mitigated the oxidative stress levels. These findings suggested that bifidocin A alleviated L. monocytogenes-induced intestinal infection by improving gut barrier dysfunction, attenuating gut inflammation, and modulating gut microbiota. Therefore, bifidocin A is a promising, and safe alternative to antibiotics for alleviating L. monocytogenes-induced intestinal infection.