A mixture containing galactooligosaccharide, produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium infection in mice

The prebiotic Bimuno® is a mixture containing galactooligosaccharide, produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41171 in the presence of lactose. Previous studies have implicated prebiotics in reducing infections by enteric pathogens, thus it was hypothesized that Bimuno® may confer some protection in the murine host from Salmonella enterica serovar Typhimurium (S. Typhimurium) infection. In this study, infection caused by S. Typhimurium SL1344nalr in the presence or absence of Bimuno® was assessed using tissue culture assays, a murine ligated ileal gut loop model and a murine oral challenge model. In tissue culture adherence and invasion assays with HT-29-16E cells, the presence of ∼2 mM Bimuno® significantly reduced the invasion of S. Typhimurium SL1344nalr (P<0.0001). In the murine ligated ileal gut loops, the presence of Bimuno® prevented colonization and the associated pathology of S. Typhimurium. In the BALB/c mouse model, the oral delivery of Bimuno® prior to challenge with S. Typhimurium resulted in significant reductions in colonization in the five organs sampled, with highly significant reductions being observed in the spleen at 72 and 96 h post-challenge (P=0.0002,