Mother-infant sharing of gut plasmid sequences during early infancy and their genetic characteristics

Maternal-infant plasmid sharing is detected in 27 of 117 comparisons (23.1%) at 0.5 and 3 months, but not at 12 months, in 65 mother-infant pairs.

• Why it matters: Maternal microbes shape early infant gut communities, yet plasmid transfer between mothers and infants is poorly characterized across infancy and in relation to delivery mode.
• What they did: Reanalyzed longitudinal shotgun metagenomes from 65 mother-infant pairs at infant ages 0.5, 3, and 12 months to find highly similar plasmid sequences across 117 comparisons, then assessed predicted hosts and gene content.
• The result: Shared plasmids were enriched for mobilization (mbpA, mbpB, mbpC), replication (repL), and toxin-antitoxin systems (yoeB), with prominent Bacteroides-associated sequences; vaginal delivery increased total plasmid counts at 0.5 months, while sharing did not differ by delivery mode.