Uberos, José2023-02-092023-02-092020http://hdl.handle.net/10668/15656The use of metagenomics in the study of gut bacterial ecosystems has helped to define a standard, functional genetic profile in newborn infants, so that a bacterial ecosystem will be deemed more "normal" the more similar its functional genetic profile is to a standard. The development of a specific functional enterotype in the first days of life after birth is critical for the priming of the immune system with certain bacterial antigens. Regardless of whether the first gut bacteria are acquired before or just after birth, the newborn microbiota will result from the symbiosis with the environmental microbial flora, especially with the bacterial flora of the mother. The type of delivery, the administration of perinatal antibiotics, the environment, and nutritional exposure, especially breastfeeding, have demonstrated an important relationship with the prevalent gut microbiome.enenterotypemicrobiomemicrobiotanewborn infantBreast FeedingDelivery, ObstetricFemaleGastrointestinal MicrobiomeHumansInfant HealthInfant, NewbornPregnancyresearch article32470263open access10.5546/aap.2020.eng.e2651668-3501https://doi.org/10.5546/aap.2020.eng.e265