Colonisation intestinale et translocation bactérienne chez la souris conventionnelle C3H/HeJ apres ingestion d’une dose unique de Bifidobacterium breve C50 vivantes ou mortes

Abstract

The efficiency and safety of use of Bifidobacterium breve C50 (BbC50), a potential probiotic, was assessed as regards intestinal microbial colonisation and bacterial translocation. A suspension of BbC50, containing 1-5 to 107-108 live bacteria, was fed to C3H/HeJ mice. The passage of live BbC50 was not demonstrated by culture either in the intestine or extra-intestinal organs. However, mice receiving the highest dose of live bacteria harbored more lactobacilli and less Bacteroides fragilis group in the cecum and colon when compared to control mice. Translocation of lactobacilli observed in the control group was not regulated by Bb50 feeding. Indeed, the spleen was significantly more frequently contaminated in mice fed BbC50, whatever the dose of live bacteria. The kidneys were also significantly more contaminated with lactobacilli in mice fed the highest dose of live Bb50. Moreover, higher dose of live BbC50 was associated with greater number of extra-intestinal contaminated organs. To conclude, BbC50 feeding induced a favorable balance in the mouse intestinal flora and was never found translocating, demonstrating its efficiency and safety of use. However, BbC50 seemed to interfere with the ability of lymphoid organs (e.g. the spleen) to eliminate translocating lactobacilli.