The effect of in-hospital breast milk intake on the gut microbiota of preterm infants

Abstract

Objective: The aim of this study was to explore the effect of in-hospital breast milk intake on the development of early gut microbiota in preterm infants in two dimensions: longitudinal over time and cross-sectional between groups.

Methods: Researchers collected preterm infants' general data baseline characteristics, recorded their daily breast milk intake, probiotics, and antibiotics use, and collected their stool specimens at 1st week, 2 nd week, 3rd week and 4th week after birth. The researchers analyzed the effect of breast milk on gut microbiota of preterm infants by bioinformatics methods of intra-group longitudinal variation of gut microbiota structure and diversity in preterm infants and cross-sectional differences between >70 % in-hospital breast milk intake (BM) group and ≤70 % (PF) group.

Results: A total of 60 preterm infants were included in this study, and a total of 213 stool specimens were retained. BM had statistically different Shannon and Simpson indices between the first and fourth week after admission (P < 0.05), both of them showed a lower diversity in the later week than in the previous week. The Shannon index and Simpson index of BM from week 3 onwards were statistically different from PF (P < 0.05), and the Shannon index and Simpson index of BM were lower than those of PF. Significantly statistical differences (P < 0.05) were found in the beta diversity of gut microbiota in preterm infants as time progressed, and both showed a lower beta diversity in the later week than in the preceding week. The dominant taxa of PF in the first postnatal week were Bifidobacterium animalis, etc., the dominant taxa of BM in the third postnatal week were Clostridium_sensu_stricto _1, etc. CONCLUSIONS: The development and evolution of gut microbiota in preterm infants' in-hospital period was a continuous, non-random process, and similar trends in species composition and changes in gut microbes emerged in preterm infants with different ratio of breast milk intake. In the NICU setting, alpha diversity was lower in preterm infants in the >70 % breast milk intake group than in the ≤70 % group when compared between groups at the same time, which may be related to delayed maturation of gut microbes and represents a more developmental gut time window.

Keywords: Breast milk; Gut microbiota; NICU; Preterm infants.