Aim: To detect the gut colonization capacity of Bifidobacterium breve CCFM1025 with clinical antidepressant-like effects. Materials & methods: A unique gene sequence of B. breve CCFM1025 was discovered based on the genome analysis of 104 B. breve strains and a strain-specific primer (1025T5) was designed. In vitro and in vivo samples were used to validate the specificity and quantitative capability of this primer in the PCR system. Results: Quantitative PCR using strain-specific primers enabled absolute quantification of CCFM1025 in fecal samples within 104-1010 cells/g (R2 >0.99). CCFM1025 remained highly detectable in volunteer feces 14 days after cessation of administration, demonstrating its favorable colonization characteristics. Conclusion: CCFM1025 can colonize the healthy human gut.
Keywords: Bifidobacterium; colonization; genome; quantification; strain-specific primers.