A study published in Cell determined the vertical and horizontal transmission of bacterial species, different strains, and individual genes to understand the dynamics of the gut microbiome assembly that influence the infants development both before and after birth. 

The researchers collected faecal and infant-serum samples from 137 women and 74 newborns, including 70 pairs of mothers and infants. The samples were analyzed using deep metagenomic sequencing, assays to gauge the levels of circulating cytokines, markers of gut inflammation, and gut permeability, as well as untargeted profiling of faecal metabolites. The study also assessed how the mothers and babies metabolomic and metagenomic profiles changed over time and how they were related.

The findings demonstrated widespread transmission of mobile genetic components, typically linked to genes involved in diet-related adaptations, from the mother to the newborn. New microbe-metabolite relationships and rare metabolites absent in mothers were abundant in infant metabolomes. The inverse link between Bifidobacterium longum and inosine, an amino acid with immunomodulatory and neuroprotective characteristics, was one such association found exclusively in infant metabolomes.

Breastfed infants experienced early immunological maturation, which led to greater immune tolerance. Breastfed infants exhibited elevated levels of foetal calprotectin and beta-defensin 2, two markers of intestinal inflammation that were inversely linked with pro-inflammatory markers. Furthermore, newborns eicosanoids and other intestinal inflammatory mediators were strongly correlated with microorganisms detected in breastfeeding.

The metabolic profiles of pregnant women also revealed modifications in faecal bile acids, which were associated with increased taurine conjugation. A higher concentration of Bilophila wadsworthia, a bacterium species that decreases sulphates and breaks down taurine, was found in the gut microbiota of pregnant women.

Overall, the findings showed that the infants′ microbiome and metabolome are co-developed by their mother′s microbiota and dietary variables, which in turn affects the infants′ neurodevelopment and immunological maturation. Additionally, interspecies horizontal gene transfer from mother to infant exerts maternal influences on the infants metabolic processes and gut flora. More research is required since the discovery of microbe-metabolite interactions specific to newborns suggests that bacteria are essential for early development.

(Source: https://www.news-medical.net/news/20221229/Horizontal-gene-transfer-from-mother-to-infant-influences-gut-microbiome-assembly-neurodevelopment-and-immune-maturation-in-infants.aspx)