Final answer:
Humans interact with microbes prenatally, and these interactions develop further postnatally, affecting the neonate's gut colonization and immune development. Methods of birth and early feeding play significant roles in shaping the microbiome. A stable microbiome is usually established by age 2-3, affecting long-term health and immunity.
Step-by-step explanation:
Humans interact with microbes even before birth, and these interactions continue to develop postnatally and throughout infancy and childhood. Research has indicated that prenatal exposure to microbes occurs early in-utero, and upon delivery, the newborn is colonized by microorganisms from the mother and the surrounding environment. During delivery, vaginal births expose the newborn to maternal Lactobacillus spp. which significantly influence early microbiome development, compared to cesarean sections where colonization comes primarily from skin microbiota and hospital-acquired pathogens.
In the immediate postnatal period, the baby's gut is rapidly colonized, and factors such as feeding methods (breastfeeding vs. formula) play a critical role in the shaping of the gut microbiome. As infants transition into childhood, the microbiome becomes more established around the age of 2 to 3 years old and generally remains stable but continues to change in relation to diet, lifestyle, and health.
The development of the microbiome is integral to the development of a child's immune memory. It plays a critical role in protection against diseases and aids in digestion among other functions. Overly clean environments and the use of antibiotics, which cannot distinguish between 'good' and 'bad' bacteria, can disrupt this balance, potentially leading to problems in the immune system functioning.
Moreover, the composition of gut microbes varies between host species and plays an essential role in their health. Gut flora, consisting of helpful bacteria in the intestine, can synthesize vitamins, prevent pathogen invasion, and contribute to immune system regulation. The symbiotic relationship we share with these bacteria is crucial for our well-being.