Intestinal Microbiome in Preterm Infants Influenced by Enteral Iron Dosing.

OBJECTIVES: The aim of the study was to compare the intestinal microbiome in very low birth weight (VLBW) infants who received different enteral iron supplementation (EIS) doses. STUDY DESIGN: Longitudinal stool collection in 80 VLBW infants were conducted up to 2 months postnatally in a prospective study. The 16S rRNA regions V4 was used to calculate microbiome compositions and the Piphillin software was used for bacterial functional prediction. Linear mixed effect models and Wilcoxon rank-sum tests were performed to examine the relationships between initial EIS dosage and stool microbiome and bacterial functional potential. RESULTS: There were 105 samples collected before and 237 collected after EIS started from infants with birth gestational age and weight of 28.1 ±â€Š2.4 weeks and 1103 ±â€Š210 g, respectively. The average postnatal age at start of EIS was 17.9 ±â€Š6.9 days and the average initial EIS dose was 4.8 ±â€Š1.1 mg ·â€Škg-1 ·â€Šday-1. Infants who were started on ≥6 mg ·â€Škg-1 ·â€Šday-1 had higher abundances of Proteus and Bifidobacterium and a lower alpha diversity than those started on lower doses (P < 0.05). Infants given higher EIS doses had higher bacterial predicted functional potentials for ferroptosis and epithelial invasion after 2 weeks post EIS. CONCLUSIONS: Higher EIS dosage is linked to higher abundances of Proteus and Bifidobacterium, and a less diverse microbiome and higher predicted potential of bacterial epithelial invasion. These observational findings should be further studied in a randomized study to elucidate the optimal dosage of EIS in VLBW infants.

Predicted Metabolic Pathway Distributions in Stool Bacteria in Very-Low-Birth-Weight Infants: Potential Relationships with NICU Faltered Growth.

Many very-low-birth-weight (VLBW) infants experience growth faltering in early life despite adequate nutrition. Early growth patterns can affect later neurodevelopmental and anthropometric potentials. The role of the dysbiotic gut microbiome in VLBW infant growth is unknown. Eighty-four VLBW infants were followed for six weeks after birth with weekly stool collection. DNA was extracted from samples and the V4 region of the 16S rRNA gene was sequenced with Illumina MiSeq. A similar microbiota database from full-term infants was used for comparing gut microbiome and predicted metabolic pathways. The class Gammaproteobacteria increased or remained consistent over time in VLBW infants. Out of 228 metabolic pathways that were significantly different between term and VLBW infants, 133 pathways were significantly lower in VLBW infants. Major metabolic differences in their gut microbiome included pathways involved in decreased glycan biosynthesis and metabolism, reduced biosynthetic capacity, interrupted amino acid metabolism, changes that could result in increased infection susceptibility, and many other system deficiencies. Our study reveals poor postnatal growth in a VLBW cohort who had dysbiotic gut microbiota and differences in predicted metabolic pathways compared to term infants. The gut microbiota in VLBW infants likely plays an important role in postnatal growth.