Bacteriocin biosynthesis contributes to the anti-inflammatory capacities of probiotic Lactobacillus plantarum

Strains of Lactobacillus plantarum produce plantaricin, a class IIb bacteriocin, and a corresponding immunity protein encoded by the genes plnEFI. In this study, we compared L. plantarum NCIMB8826 and a ΔplnEFI delection mutant of that strain LM0419 in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced mouse model of inflammatory bowel disease. Mice fed L. plantarum NCIMB8826 exhibited intermediate (non-significant) reductions in intestinal inflammation compared to the TNBS-administered and healthy controls. By comparison, intestinal tissue damage and serum IL6 levels were higher in mice given L. plantarum LM0419 and equivalent to the TNBS-treated mice. Both strains survived digestive tract transit in equal numbers and did not result in global changes to the bacterial composition in the mouse stools and cecal contents either prior to or after TNBS administration. Instead, taxonomic analysis showed that mice consuming wild-type L. plantarum but not LM0419 contained lower proportions of Mucispirillum (Deferribacteres phylum) in the feces prior to TNBS administration and Parabacteroides (Bacteroidetes phylum) in the cecum after disease induction. Parabacteroides also positively associated with disease activity and host inflammatory markers. These findings suggest a role for bacteriocin production by probiotic Lactobacillus in benefiting digestive tract health.