313 - Decreased Microbial Diversity Suggests Greater Activity in Pediatric Crohn’s Disease

Abstract:

Background: The prevalence and incidence of Crohn’s Disease (CD) in pediatric populations has continued to increase. Growing evidence suggests that gut microbiome dysbiosis plays a critical role in the pathogenesis of CD. However, diagnosing CD over other functional gastrointestinal disorders (FGIDs) remains challenging.

Hypothesis: Compared to patients with FGIDs, pediatric patients with newly diagnosed, treatment-naïve Crohn’s Disease (CD) will exhibit decreased alpha diversity and an increased abundance of pro-inflammatory bacteria, which will correlate with higher disease activity as measured by the Pediatric Crohn’s Disease Activity Index (PCDAI).

Methods: Our study investigated the fecal microbiome of newly diagnosed, treatment-naïve pediatric CD patients (n=43) compared to age- and sex-matched controls with Functional Gastrointestinal Disorders (FGID) (n=139). We performed paired-end (2x300 bp) 16S rDNA sequencing of the V3-V4 region on an Illumina MiSeq. The QIIME2 platform was used to obtain fecal sample microbial community composition.

Results: Our results found that microbial richness and diversity were significantly lower in CD patients. Furthermore, differential relative abundance analysis showed enrichment in phyla harboring pro-inflammatory bacteria (Fusobacteria & Proteobacteria) and depletion in favorable bacteria (Firmicutes & Verrucomicrobia). These microbial changes, a decrease in alpha diversity, were correlated to increased PCDAI scores. Specifically, higher PCDAI scores were linked to the enrichment of pro-inflammatory genera (Hungatella and Veillonella) and depletion of the protective genus (Lachnospiraceae).



Identify Supporting Agency and Grant Number: Research supported by The Leona M. and Harry B. Helmsley Charitable Trust (grant # 1911-03329).