Impact of breast milk microbiota on the neonatal intestinal microbiota according to delivery type and circumstances, a cross-sectional study

Background: Bacterial colonization of the neonatal gut has imperative consequences on the health and development of the newborns. Aim: To assess the impacts of maternal breast milk microbiota and other perinatal factors on the colonization and construction of newborns’ gut microbiota. Methods: Specimens from mothers’ milk and neonatal stool, from 40 mother-infant pairs, were subjected to real time polymerase chain reaction (qPCR) analysis, to assess the effect of mothers’ milk microbiota on bacterial composition of the neonates’ gut in the view of different modes of delivery and different circumstances. Results: The study showed that Bifidobacterium was the most abundant bacterial species detected in both neonates’ stool and breast milk. There was a significant higher level of stool Bifidobacterium in neonates who were exclusively breastfed. Maternal milk Bifidobacterium increased significantly in mothers who breastfed their neonates exclusively. Antibiotics administration, either in neonates or their mothers, was negatively associated with the presence of stool Bifidobacterium and Streptococcus spp. Our results indicated that neonatal age, weight, sex, and mode of delivery showed no considerable association with any microbiota, either in the stool or milk. Milk Bifidobacterium and Streptococcus spp. decreased significantly in mothers receiving antibiotics; however, stool Staphylococcus spp. increased significantly in either neonates who needed respiratory support or their mothers lived in urban communities. Conclusion: Promotion of early and exclusive breast milk feeding for neonates has a great impact on shaping neonatal gut microbiota. Its importance becomes much augmented when neonates are admitted to NICUs and subjected to antibiotics, regardless of the mode of delivery.