# Microbial signature of pediatric Crohn's disease: Differentiation from functional gastrointestinal disorders and relationship with increased disease activity

## TL;DR

This study shows that the gut microbiome of children with Crohn's disease differs significantly from those with other gut issues and correlates with disease severity.

## Contribution

The study identifies specific microbial signatures linked to pediatric Crohn's disease and its activity levels.

## Key findings

- CD patients had lower microbial richness and diversity compared to controls.
- Pro-inflammatory bacteria like Fusobacteria and Proteobacteria were more abundant in CD patients.
- Higher disease activity was associated with increased Hungatella and Veillonella and reduced Lachnospiraceae.

## Abstract

The prevalence and incidence of Crohn's disease (CD) in pediatric populations have been steadily increasing. Growing evidence suggests that gut microbiomal community differences play a critical role in the pathogenesis of CD. Additionally, the clinical course of patients with CD is unpredictable, making treatment decisions challenging. We investigated the fecal microbiome of newly diagnosed, treatment‐naïve pediatric CD patients (n = 43) compared to age‐ and sex‐matched controls with other functional gastrointestinal disorders (n = 139). We also correlated microbial changes with CD disease activity, measured by the Pediatric Crohn's Disease Activity Index (PCDAI). Our results showed that microbial richness and diversity were significantly lower in CD patients. Furthermore, taxonomic analysis revealed an enrichment in pro‐inflammatory bacteria (Fusobacteria and Proteobacteria) and depletion in favorable bacteria (Firmicutes and Verrucomicrobia). Higher PCDAI scores were linked to the enrichment of genera harboring pro‐inflammatory taxa (Hungatella and Veillonella) and decreased abundance of genera harboring protective taxa (Lachnospiraceae). Our study underscores the potential of fecal microbiome profiling as an effective tool for understanding CD pathogenesis, identifying microbial biomarkers, and predicting disease activity for treatment response. This, in turn, can help to improve personalized treatment and management strategies in pediatric CD.