Comparison of the Gut Microbiota of Preterm Infants Born before 32-Week Gestation with Feeding Intolerance

Purpose: Feeding intolerance (FI) is a prevalent clinically sequential condition in preterm infants. To clarify its relationship with the gut microbiota, we compared microbial diversity and taxonomic composition at 2 and 4 weeks of age in infants born before 32 weeks of gestation.Methods: Between August 2021 and December 2022, we prospectively enrolled infants who delivered before 32 weeks of gestation and were admitted to the neonatal intensive care unit at CHA Bundang Medical Center. Forty-four preterm infants were grouped based on the presence (n=16) or absence (n=28) of FI. Fecal samples were obtained at 2 and 4 weeks after birth and analyzed using 16S rRNA gene sequencing to determine microbial profiles.Results: Microbial α-diversity and β-diversity did not differ significantly between groups at either time point. At the genus level, <i>Staphylococcus</i> was significantly more abundant in the FI group than in the feeding tolerance group at 2 weeks postnatal age (<i>P</i>=0.016). Linear discriminant analysis effect size revealed that <i>Staphylococcus, Pseudomonas,</i> and <i>Escherichia</i> were markedly enriched in the FI group at all time points.Conclusion: Early colonization by potentially pathogenic genera, particularly <i>Staphylococcus,</i> may precede the development of FI in preterm infants. These findings highlight the potential microbial composition associated with FI and may provide preliminary insights for future microbiome-targeted research in neonatal care.