Citrobacter and Acinetobacter are respectively involved in feeding intolerance in preterm infants of different gestational ages: a prospective case-control study.

Background: Feeding intolerance (FI) is a common feeding problem in preterm infants. The gut microbiota contributes significantly to its onset, progression, and outcome. In this study, we aimed to understand the differences in gut microbiota among preterm infants with FI of different gestational ages. The goal was to provide a basis for early probiotic intervention.

Methods: We undertook a prospective case-control study in which we enrolled 80 preterm infants at a gestational age < 34 weeks. Participants were divided into four groups of 20 each: early preterm infants with FI (EFI group, gestational age < 32 weeks), early preterm infants with feeding tolerance (FT) (EFT group, gestational age < 32 weeks), moderate preterm infants with FI (MFI group, gestational age ≥ 32 weeks), moderate preterm infants with FT (MFT group, gestational age ≥ 32 weeks). 16 S rDNA high-throughput sequencing was employed to analyze the infants' fecal microbiota and examine the potential link between gut microbiota and gestational age. Statistical analysis was conducted for the collected data. The Statistical Package for Social Sciences software was used. T-tests or non-parametric tests were performed for comparison between groups of measurement data, and the χ2 test was used to compare between groups of count data. At the genus and species level, the potential association between intestinal microbiota and FI and the relationship with gestational age were explored.

Results: The abundance of Citrobacter in the feces of the EFI group was significantly higher than that in the EFT group. Additionally, the abundance of Acinetobacter in the MFI group was significantly higher than that in the MFT group. The abundance of Clostridium XI was significantly low in the MFT group.

Conclusions: Citrobacter and Acinetobacter genera are implicated in FI in preterm infants with gestational ages < 32 weeks and ≥ 32 weeks, respectively. However, Clostridium XI may be involved in regulating intestinal homeostasis in those with a gestational age ≥ 32 weeks.

Trial registration: ChiCTR, ChiCTR2400086000. Registered 24 June 2024, https://www.chictr.org.cn/showprojEN.html?proj=210,126 .