700 - Can the Composition of the Neonatal Gut Microbiome Predict Necrotizing Enterocolitis?

Publication Number: 1677.700

Heather E. Croy, Sidney Kimmel Medical College at Thomas Jefferson University/duPont Hospital for Children, Philadelphia, PA, United States; Amy B. Mackley, Christiana Care Health System, Newark, DE, United States; Kelley Kovatis, ChristianaCare, Newark, DE, United States

Background: Necrotizing Enterocolitis (NEC) continues to be a leading cause of morbidity and mortality among premature neonates. New evidence suggests that alternations in the intestinal microbiome may play a role in the development of NEC. Characterizing microbial shifts preceding clinical symptoms may provide insight into the pathogenesis of NEC. A deeper understanding of the microbiome may allow the development of targeted preventive strategies.

Objective: The primary aim of this study was to compare the intestinal microbiota of healthy preterm infants to preterm infants who developed NEC. We hypothesize, stool from infants who develop NEC will have decreased diversity.

Design/Methods: The study was approved by the Christiana Care Institutional Review Board. Stool samples were collected from infants born at ≤32 weeks born between May 2023-May 2024. 8 patients developed NEC and were matched by gestational age and birthweight 2:1 to healthy controls. Stool was collected at 0-2 days, 2 weeks, and 1 month. Stool collection ended when an infant developed NEC or required transfer for surgical evaluation. Stool samples were stored in a -80 ºC freezer until processing. Demographic and clinical characteristics were summarized using descriptive statistics. DNA extraction and sequencing were completed using PCR-based16s ribosomal targeted metagenomic sequencing (16s rRNA amplicon-seq). Advanced negative-binomial generalized linear model (NB-GLM) statistical analysis was performed.
Definitions: Alpha diversity measures the total number of microbial species. Beta diversity describes the microbiota composition shifts between groups.

Results: There was no difference in baseline demographic and clinical data for both groups (Table 1). There was a significant increase Alpha diversity in the healthy controls but not in the NEC group over time. Additionally, there was no difference in the alpha diversity at equivalent time points (Fig 1). Beta diversity was increased in the healthy controls but not the NEC group. NEC group had less transition in enterotype over time (Fig 2). Clostridium was present in the first stool only in the NEC group.

Conclusion(s): Patients who developed NEC had decreased diversity of microbiota, less transition of enterotypes over time, and possibly pathogenic colonization at birth prior to the diagnosis of NEC. This indicates that changes in the microbiome early in life, even prior to delivery, could be contributing to the development of NEC in these patients. Targeting alterations in the gut microbiome prior to the onset of NEC may offer a promising strategy for disease prevention.

Table 1


Figure 1
Figure 1. Alpha Diversity comparison between all three timepoints (1, 2, and 3) using Chao-1 index in the Health Controls and NEC groups. Chao-1 index measures the estimated total number of taxa in the given microbiota. **: p <= 0.01, ***: p <= 0.001, ****: p<= 0.0001; Tube-group: matched sample group IDs using various clinical factors.

Figure 2
Figure 2: (A) Microbial compositions of 7 different types of microbiota communities (cm1 ~ cm7) using a Dirichlet-Multinomial Mixture model (DMM) based on the most abundant microbial taxa. The estimated relative abundance of individual microbial taxon was based on the fitted values in the DMM model. Only the aggregated compositions at taxonomic family level is shown for visualization purpose. (B) Heat map of predicted enterotype across each time point in Healthy Controls and NEC groups. The enterotype is represented by the predicted, most likely, microbial community using the DMM model. Matched patients from the same groups using various clinical factors are organized in the same rows.