A joint work by the Institute of Biomedicine of Valencia (IBV) and the Institute of Agrochemistry and Food Technology (IATA), both from the Spanish National Research Council (CSIC), has demonstrated the influence of breastfeeding on the configuration of the gut phageome, the collection of viruses that attack bacteria in our microbiota. The study, published in the journal Cell Reports Medicine, analyzes how this viral ecosystem changes during the baby's first twelve months of life, moving from a simpler structure associated with breastfeeding to greater diversity with complementary feeding.
The research is part of the MAMI cohort, a follow-up of mothers and children in the Valencian Community from birth. Fecal samples from babies were analyzed at seven days, one month, six months, and twelve months, along with maternal and milk samples. Through metagenomic analyses, 6,248 non-redundant viral populations were identified. Initially, the infant phageome is simple, with few viruses accounting for a large part of the abundance, notably those associated with bacteria like Bifidobacterium.
Viral diversity progressively increases throughout the first year, rising from about 56 viral populations per sample in the first week to around 160 at 12 months. "Understanding how diet influences phageome evolution allows us to better know the relationships established between viruses and their intestinal host bacteria during a key developmental stage," states Alberto Marina, a researcher at IBV-CSIC and co-author of the study. "Bacteriophages are part of the intestinal ecosystem from the first days of life and change as the microbiota also changes."
The results suggest that diet is the most consistently associated factor with the phageome. Breastfed babies show a higher presence of Bifidobacterium phages, while with weaning and the introduction of complementary feeding, phages associated with bacteria like Lachnospiraceae and Ruminococcaceae, more characteristic of intestinal maturation, appear.
The study also analyzed the overlap of phage populations between mothers and babies. "We found shared viral populations between mother and baby, and we observed that this overlap changes as development progresses. The results are compatible with a maternal contribution, but we need more studies to determine which phages are transmitted and what function they play," explains Elena Cabello Yeves, a researcher at IBV-CSIC and lead author.
This research expands knowledge on infant microbiome development by incorporating the role of bacteriophages and their interactions with bacterial communities. "These viruses can modify bacterial populations and participate in genetic exchange between them," concludes the team, which includes collaborators from CSIC, CIBERER, CIBERESP, and universities in the United Kingdom.
