Using state-of-the-art molecular approaches, 16S rRNA next generation sequencing and “bulk” DNA gene sequencing, the objectives are:
1) to define the microbial diversity and the “gold standard” or “reference” microbial community composition for the “well” VLBW infant fed mother's milk.
2) to characterize how the two most commonly used supplements of mother's milk, donor milk and preterm formula, modify microbial diversity and the “reference” microbial community composition.
3) to characterize how nutrient fortification of mother's milk and donor milk modify microbial diversity and microbial community composition.
4) to define the potential metabolic functions available to the gut microbiome of infants fed mother's milk, donor milk and preterm formula.
5) to assess which taxa are the best predictors of feeding intolerance and a composite outcome of mortality or major morbidity.
This is a prospective observational study of a subset of 135 VLBW infants enrolled in a trial designed to evaluate the effectiveness of donor milk compared to formula as a supplement to mother's milk (see DoMINO). Analysis will involve a three group comparison based on how infants were fed during hospitalization: (1) exclusively mother's milk, (2) any donor milk, (3) any preterm formula. Stool samples will be collected weekly for eight weeks. Bacterial DNA will be extracted from stools and amplified by Polymerase Chain Reaction using 16S rRNA bacterial genotyping. Metabolic functions in the microbiome associated with feeding type will also be identified in a subset of stools. Data on feeding type and fortification, variables that may affect colonization, feeding tolerance, mortality, and major morbidities will be collected from medical records.