Project 458944

Preterm, very low birth weight (VLBW; birth weight < 1,500 g) infants are born with an immature gastrointestinal tract and a gut bacterial community that is typically perturbed or imbalanced. Encouragingly, the intake of mother's milk was found to be a modifiable factor that may help optimize the bacterial communities in the preterm infant gut. It is thought that the bacteria in mother's milk, known as the milk microbiota, provides beneficial bacteria to colonize the infant's gut. Mother's milk also contains oligosaccharides, which are complex sugars, that promote the growth of beneficial bacteria. However, our understanding of the human milk microbiota, human milk oligosaccharides (HMOs), and their impact on the infant's gut microbiota has largely been derived from healthy term infants, which may not be transferrable to the underdeveloped VLBW infant. Therefore, the overarching aim of this doctoral research is to determine how the mother's milk microbiota and oligosaccharides impact the gut bacterial communities in a VLBW infant's gut. As part of the recently completed randomized controlled trial, OptiMoM (Optimizing Mothers' Milk for Preterm Infants; NCT02137473) fortifier study, weekly stool and human milk samples were prospectively collected for 127 preterm infants born <1250g, for 8 weeks or until discharge. Sophisticated molecular techniques will be used to study the milk microbiota, oligosaccharide profiles, and their relationship with the gut microbiota of infants. This study will provide foundational knowledge about the impact of mother's milk on the gut colonization of VLBW infants and may inform the development of future interventions targeted towards rehabilitating perturbed gut microbiomes.