How can a C-Section affect the baby’s gut?

Learning about our baby’s gut at time of birth gives researchers an opportunity to study the development and colonization of the infants’ gut microbiome as they get exposed to a variety of microorganisms in the early stage of life. The neo-natal period (first 21 days of life) is crucial for the infants’ microbiome in terms of shaping the future of their gut flora expansion depending on the type of microorganisms encountered.

This Baby Biome Study (BBS) involved the participation of 596 healthy, carried to full term babies 314 of which were vaginally born and 282 births by cesarean section. Fecal samples were retrieved at least once from all babies during the first month of life and 302 babies went through another round of sample collection as they approached their first year of life (8.75 ± 1.98 months). Fecal samples from 175 mothers were also collected in coupling with 178 babies. With the help of next generation whole genome sequencing a total of 1679 fecal samples were processed and analyzed to show how a “blank canvas” of gut microbiota is adapting and progressing with age. As one would suspect no individual gut flora is the same considering millions of various bacteria are involved; the results presented high diversity and instability within the same group. As much as 57% of diversity in the bacterial communities was found when comparing vaginal versus cesarean mode of birth. When comparing maternal microbiomes of the two respective groups, no significant difference was found. However, the scientist noticed that with time the babies’ differences in diversity of their gut microbiotas decreased. The vaginal mode of delivery cohort microbiome was enriched with bacteria from genera such as Bifidobacterium, Escherichia, Bacteroides and Parabacteroides making up 68.3% of the gut flora. Originally it was thought the infant picks up this community of bacteria from the mother’s vaginal tract, but it turns out the bacteria are inherited from the mother’s gut. The Cesarean section babies, however, showed a mix of Enterococcus faecalis, Enterococcus faecium, Staphylococcus epidermis, Streptococcus parasanguinis, Klebsiella oxytoca, Klebsiella pneumoniae, Enterobacter cloacae and Clostridium perfringens taking over 68.3% of diversity in the gut microbiota. These particular set of bacteria are often affiliated with the hospital environment and are considered to be opportunistic pathogens. Interesting enough, the scientists isolated the colonies of these pathogenic species to take a closer look at the epidemic level of these guys. Any level of opportunistic pathogen can increase a risk of future infections;  in this case the isolated strains showed non epidemic lineages of virulence. In other words, just because the microbiota houses these particular pathogens doesn’t necessarily mean that they will have an effect on the host’s health. To find out long term effects of the cesarean baby gut bacterial community, more longitudinal, larger cohort studies over longer periods of time are required.