Influence of Feeding Type on Gut Microbiome Development in Hospitalized Preterm Infants

BACKGROUND: Premature infants have a high risk for dysbiosis of the gut microbiome. Mother's own milk (MOM) has been found to favorably alter gut microbiome composition in infants born at term. Evidence about the influence of feeding type on gut microbial colonization of preterm infants is limited. OBJECTIVE: The purpose of this study was to explore the effect of feeding types on gut microbial colonization of preterm infants in the neonatal intensive care unit. METHODS: Thirty-three stable preterm infants were recruited at birth and followed up for the first 30 days of life. Daily feeding information was used to classify infants into six groups (MOM, human donor milk [HDM], Formula, MOM + HDM, MOM + Formula, and HDM + Formula) during postnatal days 0-10, 11-20, and 21-30. Stool samples were collected daily. DNA extracted from stool was used to sequence the 16S rRNA gene. Exploratory data analysis was conducted with a focus on temporal changes of microbial patterns and diversities among infants from different feeding cohorts. Prediction of gut microbial diversity from feeding type was estimated using linear mixed models. RESULTS: Preterm infants fed MOM (at least 70% of the total diet) had highest abundance of Clostridiales, Lactobacillales, and Bacillales compared to infants in other feeding groups, whereas infants fed primarily HDM or formula had a high abundance of Enterobacteriales compared to infants fed MOM. After controlling for gender, postnatal age, weight, and birth gestational age, the diversity of gut microbiome increased over time and was constantly higher in infants fed MOM relative to infants with other feeding types (p < .01). DISCUSSION: MOM benefits gut microbiome development of preterm infants, including balanced microbial community pattern and increased microbial diversity in early life.