NICU infant gut microbiota development. Gut microbiota development of NICU preterm infants

Gut microbiome development affects infant health and postnatal physiology. The gut microbe assemblages of preterm infants have been reported to be different from that of healthy term infants. However, the patterns of ecosystem development and inter-individual differences remain poorly understood. We investigated hospitalised preterm infant gut microbiota development using 16S rRNA gene amplicons and the metabolic profiles of 268 stool samples obtained from 17 intensive care and 42 term infants to elucidate the dynamics and equilibria of the developing microbiota. Infant gut microbiota were predominated by gram-positive cocci, Enterobacteriaceae or Bifidobacteriaceae, which showed sequential transitions to Bifidobacteriaceae-dominated microbiota. In NICU preterm infants, Staphylococcaceae abundance was higher immediately after birth than in healthy term infants, and Bifidobacteriaceae colonisation tended to be delayed. No specific neonatal intensive care unit-cared infant enterotype-like cluster was observed, suggesting that the constrained environment only affected the pace of transition, but not infant gut microbiota equilibrium. Moreover, infants with Bifidobacteriaceae-dominated microbiota showed higher acetate concentrations and lower pH, which are associated with host health. Our data provides an in-depth understanding of gut microbiota development in intensive care-nursed preterm infants and complements earlier studies. Understanding the patterns and inter-individual differences of the preterm infant gut ecosystem is the first step towards controlling the risk of diseases in premature infants by targeting intestinal microbiota.