There are many different potential factors that could affect an infants colonization of microbial communities, here is a list of some:
- The method of infant feedings: There are differences in gut microbiota between breastfed infants and formula-fed infant. The major organism in breastfed infant is Bifidobacteria while the formula-fed infants have Enterococci and Clostridia mostly. The breastfed infants have more bacterial cells and less species diversity. The methods of feeding have effects on infant’s oral microbiome also.
- Delivery method: Gut microbiome is affected by the delivery method of the infant, between vaginal birth or C-section. Infant born by C-section have a higher number of antibiotic-resistance genes compared with infants born vaginally. The gut microbiota of vaginally born infant is colonized by bacteria from maternal vagina including the enrichment in the Prevotella, Sneathia, and Lactobacillus group. The infant born by C- section has delayed colonization of the phylum Bacteroidetes and alpha diversity during first 2 years of life.
- Changes in Gut microbiome during pregnancy: The first trimester of pregnancy the mothers gut microbiome is similar to a healthy non-pregnant woman, by the third trimester, it has changes significantly. These changes are characterized by increased members of actinobacteria and Proteobacteria phyla, as well as a decrease in woman’s richness. Also woman gain weight, insulin insensitivity, and greater inflammatory.
