Transmission and dynamics of mother-infant gut viruses during pregnancy and early life

Early development of the gut ecosystem is crucial for lifelong health. While
infant gut bacterial communities have been studied extensively, the infant gut
virome remains under-explored. To study the development of the infant gut
virome over time and the factors that shape it, we longitudinally assess the
composition of gut viruses and their bacterial hosts in 30 women during and
after pregnancy and in their 32 infants during their first year of life. Using
shotgun metagenomic sequencing applied to dsDNA extracted from VirusLike Particles (VLPs) and bacteria, we generate 205 VLP metaviromes and 322
total metagenomes. With this data, we show that while the maternal gut virome composition remains stable during late pregnancy and after birth, the
infant gut virome is dynamic in the first year of life. Notably, infant gut viromes
contain a higher abundance of active temperate phages compared to maternal
gut viromes, which decreases over the first year of life. Moreover, we show that
the feeding mode and place of delivery influence the gut virome composition
of infants. Lastly, we provide evidence of co-transmission of viral and bacterial
strains from mothers to infants, demonstrating that infants acquire some of
their virome from their mother’s gut.