Distinct gut microbiota and bile acid profiles in pediatric inflammatory bowel disease versus functional gastrointestinal disorders: potential for non-invasive discrimination

Differentiating pediatric inflammatory bowel disease (IBD) from functional gastrointestinal disorders (FGID) is clinically challenging due to symptom overlap. This study aims to identify and compare distinct gut microbial and fecal bile acid profiles between these conditions to identify potential non-invasive discriminatory biomarkers for differentiating these conditions. In this case-control study, fecal samples from 33 pediatric IBD patients and 28 FGID patients were analyzed. Gut microbiota composition was assessed via 16S ribosomal RNA gene sequencing, and bile acid profiles were quantified using liquid chromatography-mass spectrometry. Statistical analyses included diversity indices, differential abundance analysis, and Spearman correlation to explore microbiota-bile acid-inflammatory marker relationships. The IBD group exhibited significantly lower gut microbial alpha diversity and distinct beta diversity compared to the FGID group. Microbiota dysbiosis in IBD was characterized by depletion of Firmicutes and the genus Blautia , and enrichment of Proteobacteria and Escherichia-Shigella . Metabolically, IBD fecal samples showed elevated primary bile acids (e.g., cholic acid) and reduced secondary bile acids (e.g., deoxycholic acid and lithocholic acid). Notably, bacteria enriched in FGID (e.g., Blautia ) positively correlated with secondary bile acids, and both were inversely correlated with inflammatory markers. Pediatric IBD and FGID demonstrate significantly different and interconnected gut microbial and bile acid metabolic profiles. The identified features, including specific bacteria and bile acids, warrant further validation as a non-invasive candidate biomarker panel with potential utility in differentiating these disorders. Not applicable (This is an observational cohort study without interventional treatment).