Anti-inflammatory effects of Bifidobacterium infantis M-63 during the early postnatal period in term infants

BACKGROUND: The administration of Bifidobacterium infantis M-63 during the early postnatal period enhances the abundance of gut Bifidobacterium, but its potential effects are still unexplored. The present study aimed to evaluate the impact of B. infantis M-63 on immunity, inflammation, gut-derived metabolites, and gut microbiota composition-based enterotypes in healthy infants. METHODS: CFU of B. infantis M-63 or placebo daily from 7 d to 3 months of age. Gut microbial composition characterization using 16S rRNA sequencing and genus-level enterotype clustering was performed. Fecal cytokine, metabolite, short-chain fatty acid, calprotectin, and secretory immunoglobulin A (sIgA) levels were measured. RESULTS: Administering Bifidobacterium infantis M-63 significantly increased gut Bifidobacterium, whereas Enterobacteriaceae abundance and proinflammatory cytokine levels decreased. Six enterotypes were identified among the gut microbiota. In Bifidobacterium-dominant enterotypes, there was a significant increase in acetic acid and tryptophan metabolite levels, and a slight increase in sIgA levels. In contrast, levels of calprotectin and inflammatory cytokines were significantly reduced compared to those in the non-Bifidobacterium enterotypes. CONCLUSIONS: Bifidobacterium-dominant enterotypes, established in the gut after administration of B. infantis M-63, were strongly associated with anti-inflammatory effects in healthy infants. IMPACT: This is the first study to demonstrate an anti-inflammatory effect in healthy full-term infants supplemented with Bifidobacterium infantis M-63 alone. Bifidobacterium-dominant enterotypes were associated with reduced levels of inflammatory cytokines and calprotectin, and increased production of beneficial tryptophan metabolites, such as Indole-3-lactic acid (ILA). This study provides evidence that supplementation with B. infantis M-63 in infants may significantly reduce inflammation during the critical early postnatal period.