Selective maternal seeding and environment shape the human gut microbiome.
Korpela K, Costea P, Coelho LP, Kandels-Lewis S, Willemsen G, Boomsma DI, Segata N, Bork P
Genome Res. 04 2018. doi: 10.1101/gr.233940.117
COMMENT: This work is focused on transmission of bacteria from mother to newborn. The authors realize that it is needed to track the specific microbial strains for clarifying where the intestinal bacteria come from, how long the initial colonizers persist, and whether colonization by other strains from the environment can replace existing ones. For tracking specific strains, they select rare single nucleotide variants in fecal metagenomes of infants and their family members and then track their vertical transmission.
As result of this analysis the authors describe the type of transmitted bacteria:
Only strains from the classes Actinobacteria and Bacteroidia, which are essential components of the infant microbiome, are transmitted from the mother and persist for at least 1 yr. In contrast, maternal strains of Clostridia, a dominant class in the mother's gut microbiome, are not observed in the infant.
The authors also describe that Caesarean-born infants show a striking lack of maternal transmission at birth.