The who, how, and when of mother-infant microbial sharing.

Most mother-infant microbial sharing involves gut-derived strains that persist into the second year of life, highlighting a significant pathway for microbiome establishment.

• Why it matters: Understanding the sources and persistence of microbial transfer is crucial for improving early-life health outcomes and developing targeted interventions to support healthy microbiome development.
• What they did: Mueller et al. analyzed microbial strains shared between mothers and infants, finding that the majority originate from the gut and can be detected up to two years after birth.
• The result: This work underscores the importance of maternal gut microbiota in shaping the infant microbiome, opening avenues for strategies to promote beneficial microbial transfer during early development.