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 ± 2.4 weeks and 1103 ± 210 g, respectively. The average postnatal age at start of EIS was 17.9 ± 6.9 days and the average initial EIS dose was 4.8 ± 1.1 mg · kg-1 · day-1. Infants who were started on ≥6 mg · kg-1 · day-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.