WIP 91 - A pilot study investigating the association of gut microbiota with severity of bronchiolitis in infants

Publication Number: WIP 91.7478

Theresa C. Barrett, NemoursAlfred I. duPont Hospital for Children, Wilmington, DE, United States; Amy Thompson, Nemours Children's Hospital, Wilmington, DE, United States; Claire E. Loiselle, Nemours Children's Hospital, Wilmington, DE, United States; Matthew Di Guglielmo, NemoursAlfred I. duPont Hospital for Children, Wilmington, DE, United States

Background: Bronchiolitis is the most common cause of infant hospitalization. The role of the gut microbiome in health and disease, including respiratory diseases, has been increasingly recognized. Prior work showed a higher likelihood of bronchiolitis in infants with a gut microbiota profile high in Bacteroides (which, in some studies, is associated with formula-feeding) and less bronchiolitis in infants with a profile high in Bifidobacteria (several studies show more Bifidobacteria in breastfed infants). This raises the question of whether gut changes associated with bronchiolitis in current studies are due to a higher proportion of formula-fed infants in bronchiolitis cohorts compared to control. It is unknown what other bacteria are associated with bronchiolitis when mode of feeding is controlled.

Objective: Determine the association between gut microbiota and bronchiolitis severity in infants while controlling for mode of feeding.

Design/Methods: This prospective, case-control study of infants aged 0-6 months admitted to the hospital with bronchiolitis is approved by the Nemours Institutional Review Board. Cases are infants with severe bronchiolitis (significant respiratory support). Controls are infants with non-severe bronchiolitis (minimal to moderate respiratory support). Infants are separated as exclusively breastfed or formula-fed. Stool samples are collected, DNA extracted and whole-metagenome sequencing performed. Preliminary studies demonstrate applicability of the extraction, sequencing, and data analysis pipeline. Enrollment will be complete in December 2024. Following sequencing and pipeline analysis, we will (1) Determine if there is a significant difference in the abundance of bacteria belonging to the genus Bacteroides and/or Bifidobacterium between case and control samples using student’s t-test; (2) Identify the genera of bacteria whose differences in abundance are most highly associated with case vs. control groups using Chi-square test and multi-variable logistic regression; and (3) Characterize diversity using relative abundances and the Shannon-Wiener index.