Microbial profile along the maternal-infant axis: Early characterization and relationships in breastfeeding women and their newborns in a Colombian population

OBJECTIVE: To characterize the maternal-infant microbiota and examine microbial relationships among the maternal gut, human milk, and infant gut microbiomes in a cohort of Colombian mother-infant pairs at a single time point within the first three months postpartum. STUDY DESIGN: A cross-sectional study was conducted with 30 mother-infant pairs. A total of 90 samples of human milk, maternal feces, and infant feces from healthy, exclusively breastfeeding pairs were analyzed to assess bacterial composition and diversity using microbiota analysis performed with 16S ribosomal RNA (rRNA) sequencing on the Illumina platform. RESULTS: The maternal gut microbiota was dominated by Subdoligranulum spp., Akkermansia spp., Christensenellaceae R-7 group, and Bacteroides spp., while the human milk microbiota was dominated by Streptococcus spp. and Staphylococcus spp. In contrast, the infant gut microbiota was primarily made up of Escherichia-Shigella spp. and Bifidobacterium spp. A total of 644 ASVs were shared among the maternal gut microbiota, human milk, and infant gut microbiota. CONCLUSIONS: This study offers the first comprehensive characterization of the maternal-infant microbial axis in a specific Colombian population, highlighting distinct microbial profiles in healthy lactating mothers, human milk, and their infants, and indicating potential microbial interactions that could be important for early-life colonization.These findings should be considered in clinical and nutritional care strategies for lactating women, as they may provide an opportunity to promote health in the mother-infant dyad. Future studies will need to investigate factors, including nutritional factors, which may influence the microbiota along the maternal-infant axis.