Microbiota and Human Milk Oligosaccharides in Premature Infants.

Gut microbiota plays an important role in infants' health. The prevalence of bifidobacteria in the gastrointestinal tract of term breastfed infants has been associated with reduced infection rates compared with formula-fed infants. However, few studies evaluated microbiota in premature infants. In an observational study of 577 preterm newborns born below 32 weeks gestation, gut microbiota was not driven by bifidobacteria but could be classified into six different clusters with regard to the most abundant bacteria present. Clusters were related to infants' maturity, perinatal determinants, and were associated with short- and long-term outcome. In another study, the effects of caesarean birth on infant gut microbiota could be alleviated by human milk oligosaccharides (HMOs) in mothers' milk. In addition, 58 infants fed with a formula enriched with 2 HMOs had microbiota closer to breastfed infants than 63 infants receiving the same formula without HMOs. The question then arose of the benefit of HMO supplementation for microbiota in premature infants. Thus, a multicenter randomized controlled intervention study of the effect of a liquid supplement containing 2 HMOs was set up. Ongoing data analysis will evaluate gastrointestinal tolerance parameters, intake of HMOs from human milk, long-term growth outcomes, fecal microbiota, and fecal biomarkers of gut maturation and immunity.