Colonization of C57BL/6 Mice by a Potential Probiotic Bifidobacterium bifidum Strain under Germ-Free and Specific Pathogen-Free Conditions and during Experimental Colitis

Abstract

The effects of at least some probiotics are restricted to live, metabolically active bacteria at their site of action. Colonization of and persistence in the gastrointestinal tract is thus contributing to the beneficial effects of these strains. In the present study, colonization of an anti-inflammatory Bifidobacterium bifidum strain was studied in C57BL/6J mice under germ-free (GF) and specific pathogen-free (SPF) conditions as well as during dextran sulfate sodium (DSS)-induced colitis. B. bifidum S17/pMGC was unable to stably colonize C57BL/6J mice under SPF conditions. Mono-association of GF mice by three doses on consecutive days led to long-term, stable detection of up to 109 colony forming units (CFU) of B. bifidum S17/pMGC per g feces. This stable population was rapidly outcompeted upon transfer of mono-associated animals to SPF conditions. A B. animalis strain was isolated from the microbiota of these re-conventionalized mice. This B. animalis strain displayed significantly higher adhesion to murine CMT–93 intestinal epithelial cells (IECs) than to human Caco–2 IECs (p = 0.018). Conversely, B. bifidum S17/pMGC, i.e., a strain of human origin, adhered at significantly higher levels to human compared to murine IECs (p < 0.001). Disturbance of the gut ecology and induction of colitis by DSS-treatment did not promote colonization of the murine gastrointestinal tract (GIT) by B. bifidum S17/pMGC. Despite its poor colonization of the mouse GIT, B. bifidum S17/pMGC displayed a protective effect on DSS-induced colitis when administered as viable bacteria but not as UV-inactivated preparation. Collectively, these results suggest a selective disadvantage of B. bifidum S17/pMGC in the competition with the normal murine microbiota and an anti-inflammatory effect that requires live, metabolically active bacteria.

Commensal Propionibacterium strain UF1 mitigates intestinal inflammation via Th17 cell regulation

“…In contrast, P. UF1 permanently colonized the gut of germfree (GF) mice, as detected in the fecal contents of these mice until day 7 ( Figure 2E). Such colonization in GF mice was expected, as P. UF1, like other beneficial (e.g., Bifidobacterium bifidum) (17) or pathogenic bacteria (e.g., Citrobacter rodentium) (18), demonstrates the same trend due to the lack of competitive commensal bacteria.…”

Potential of myricetin to restore the immune balance in dextran sulfate sodium-induced acute murine ulcerative colitis

“…Myricetin (purity >95%) was purchased from the National Institutes for Food and Drug Control (Beijing, China) and dissolved in water. For the induction of acute experimental colitis, the mice were exposed to 2% DSS for consecutive 7 days …”

Exploring the role of the microbiota member Bifidobacterium in modulating immune-linked diseases

“…Studies have also shown that the effects of bifidobacteria are only exerted, or are increased, when live bifidobacteria are used. Grimm et al [64] showed that the beneficial effects of B. bifidum S17 in DSS colitis were seen from only live and not UV-killed bacteria, and Hsieh et al [57] showed that only live B. bifidum had a restorative effect on a TJ impaired Caco-2 cell monolayer. They found that acetate and formate were produced more by B. bifidum than by B. adolescentis.…”