# Analyzing the Responses of Enteric Bacteria to Neonatal Intensive Care Supplements

## TL;DR

This study shows that certain supplements given to premature infants can promote the growth of harmful gut bacteria, suggesting that supplement choices may affect gut health.

## Contribution

The study reveals how different neonatal supplements differentially affect the growth of commensal and pathogenic gut bacteria in preterm infants.

## Key findings

- Fortification of human milk significantly elevated the growth of all tested microbes.
- Iron supplements promoted the growth of pathobionts, while vitamin mixes favored commensal bacteria.
- Formula and fortified milk provided a growth advantage to pathobionts in the preterm gut.

## Abstract

In the neonatal intensive care unit, adequate nutrition requires various enteral products, including human milk and formula. Human milk is typically fortified to meet increased calorie goals, and infants commonly receive vitamin mixes, iron supplements, and less frequently, thickening agents. We examined the growth of 16 commensal microbes and 10 pathobionts found in the premature infant gut and found that formula, freshly pasteurized milk, and donated banked milk generally increased bacterial growth. Fortification of human milk significantly elevated the growth of all microbes. Supplementation with thickeners or NaCl in general did not stimulate additional growth. Vitamin mix promoted the growth of several commensals, while iron promoted growth of pathobionts. These data indicate that pathobionts in the preterm gut have significant growth advantage with preterm formula, fortified donor milk, and supplemented iron and suggest that the choice of milk and supplements may impact the infant gut microbiota.