Infants share over a third of gut microbiome with mothers, University of Colorado study finds

A University of Colorado Anschutz study published in Cell Reports reveals that infants aged 2 to 4 months share 35% of their gut microbiome species with their mothers, primarily sourced from the maternal gut rather than the vagina. Infants delivered vaginally share significantly more species (38%) than those born via C-section (24.7%). Researchers note that post-birth interventions like breastfeeding, prebiotics, and targeted probiotic species can help restore microbial colonization.

Maternal-infant microbiome sharing

• ▪A University of Colorado Anschutz-led study published in Cell Reports found that infants at 2 to 4 months of age share an average of 35% of gut microbiome species with their mothers.
• ▪In the University of Colorado Anschutz study of 68 mother-infant pairs, the maternal gut microbiome contributed 33.7% of shared species, while the maternal vaginal microbiome contributed 1.8%.
• ▪Using shotgun metagenomic sequencing and StrainPhlAn strain tracking, University of Colorado Anschutz researchers differentiated species and strains of microbes shared between mothers and infants.

Cesarean delivery microbiome effects

• ▪Interruption of maternal-infant microbe sharing caused by C-section delivery can be restored postnatally through breastfeeding and a prebiotic-rich infant diet, according to lead author Noel T. Mueller.
• ▪The University of Colorado Anschutz study showed infants delivered vaginally shared 38% of gut microbiome species with their mothers, compared to 24.7% among infants delivered by C-section.

Bacteroides colonization patterns

• ▪Certain species within the bacterial genera Bacteroides and Bifidobacterium help break down human milk oligosaccharides, which are specialized carbohydrates present in human breast milk.
• ▪University of Colorado Anschutz researchers focused on the genera Bacteroides and Bifidobacterium, which act as early gut colonizers, assist immune training, and exhibit delayed colonization after C-section delivery.

Bifidobacterium species distribution

• ▪Breastfeeding in infants was associated with a higher ratio of Bifidobacterium infantis to Bifidobacterium longum in the infant gut microbiome.
• ▪Bifidobacterium infantis is the Bifidobacterium species most adept at breaking down human milk oligosaccharides found in breast milk, according to lead author Noel T. Mueller.

Breastfeeding microbiome restoration

• ▪Introducing Bifidobacterium infantis alongside human milk oligosaccharides can help the microbe engraft in the gut of infants who did not acquire it from their mothers.
• ▪For non-breastfed infants, formula alternatives containing human milk oligosaccharides and prudent antibiotic use can help preserve and support the infant microbiome.

Maternal disease risk transmission

• ▪Lead author Noel T. Mueller noted that because the study was observational, experimental randomized controlled trials are needed to confirm causality and test microbiome restoration interventions.
• ▪Higher shared risk between mothers and children for non-genetic conditions like obesity, asthma, and eczema prompted University of Colorado Anschutz researchers to evaluate maternal microbiome transfer.