Microbiota and short chain fatty acid relationships underlie clinical heterogeneity and identify key microbial targets in irritable bowel syndrome (IBS).
Level 4 - case-series / case-control
Case-control cross-sectional observational study comparing IBS patients to healthy controls.
PubMed 41068306 · doi:10.1038/s41598-025-19363-2
What was done
Stool microbial metagenomes, stool short chain fatty acids (SCFAs), stool bile acids, colonic transit, and stool form were analyzed in 41 patients with irritable bowel syndrome (IBS-C and IBS-D) and 17 healthy controls (total n = 58). Investigators used partial canonical correspondence analyses (pCCA) conditioned on transit to quantify microbe-SCFA associations. Microbial gene pathways for substrate utilization, carbohydrate degradation, and mucin degradation were compared across clinical subgroups, subsets stratified by stool form, and patients with versus without bile acid malabsorption (BAM).
What was found
Microbe-SCFA associations differed across groups: Dorea sp. CAG:317 and Bifidobacterium pseudocatenulatum were identified as key taxa in IBS-D, whereas Akkermansia muciniphila and Prevotella copri were key in IBS-C. The highest number of microbe-SCFA associations occurred in IBS-D. Several SCFA-producing species showed inverse correlations with SCFA levels. IBS participants had fewer taxa associated with acetate-to-butyrate ratios compared to healthy controls. Differential abundance of microbial pathways for SCFA metabolism and carbohydrate/mucin degradation occurred across stool-form groups, and SCFA-producing taxa were reduced in IBS-D patients with BAM. Specific numerical values and confidence intervals were not reported in the abstract.
Why it matters
This study shows that functional microbial pathways and SCFA profiles differ by IBS subtype and bowel characteristics independent of transit time. Identifying these subtype-specific microbial drivers helps pinpoint targeted microbial and metabolic therapies for heterogeneous IBS populations.
Limits
The study is limited by a small sample size (41 patients across two subtypes and 17 controls), which reduces power for subgroup analyses (e.g., BAM status). The cross-sectional design cannot establish causality between microbial composition, SCFA shifts, and IBS symptoms. The abstract does not provide exact numeric effect sizes, statistical thresholds, or dietary control data.
Cited by
- supports Some patients have high levels of Akkermansia muciniphila in their microbiome yet fail to produce significant levels of short-chain fatty acids.