Factors that influence the colonization of the microbial community in a newborn infant:
Vaginal vs. Cesarean Section Birth. I have learned in the past in my immunology course that when infants are born vaginally, they ingest the mother’s secretions on the way out of the birth canal and that colonizes in the gut of the infant and becomes the flora (positive impact). If a baby is born through a cesarean section, I have learned in the past that a vaginal swab is used to transplant microbes from the mother into the babies mouth to colonize in the gut. If these microbes are not transplanted this could have a major negative impact on the colonization of gut microbes and I would imagine this infant could have serious digestive problems in the future. Another option is the baby not having a vaginal bacteria transplant and instead being exposed to the mother’s skin microbes only, as noted in the mini lecture this week. I have not studied if these skin microbes are better or worse or no different than vaginal microbes to colonize the gut, but I can imagine it would have a dramatic effect on gut microbial diversity.
Living/environmental conditions. After the infant is born, it will be exposed to an overwhelming amount of microbes from their surroundings. These microbes could have a positive impact or negative impact on the gut microbial community depending on the behavior of the microorganism in the gut. If the microbe is pathogenic, this will definitely negatively impact the microbiota.
Exposure to antibiotics and vaccines. Being exposed to antibiotics at a young age could wipe out bacteria that are attempting to colonize and disrupt the gut microbial community impacting it negatively. Vaccines could do this as well, but I would imagine in a more positive way that would decrease the number of pathogenic bacteria present in the infants body.
Genetics. Perhaps the baby’s genetics could alter the phenotype from normal gut conditions to acidic or basic conditions, making it a hard place for good or bad bacteria to colonize that are normally members of the gut microbial community. The diversity of the microbiota could be altered this way.