Gut Lining, Not Stool, Key to Crohn's Disease Dysbiosis, Suggests Study
India: A recent prospective study published in the Indian Journal of Gastroenterology in June 2026 reveals that the functional metabolic changes of Crohn's disease are uniquely locked in the gut lining rather than in stool. Comparing 34 treatment-naïve active patients with 33 in remission, researchers found that mucosal tissue hosts distinct microbial profiles that fecal samples fail to capture.
To understand microbial dysbiosis without the confounding effects of medical treatments, evaluating the gut microbial community before therapeutic intervention is essential. Addressing this critical clinical gap, a research team led by Amit Kumar Dutta, Dilip Abraham, Blossom Benny, Karthikeyan Govindan, and Anjilivelil Joseph Joseph aimed to compare the microbial communities in both rectal mucosal tissue and stool samples from treatment-naïve active CD patients with those in remission.
Therefore, the prospective study compared stool and rectal biopsy specimens from 34 therapy-naïve adults with active Crohn's disease (Crohn's Disease Activity Index > 150) and 33 patients in remission. Extracted bacterial deoxyribonucleic acid was sequenced on the Illumina MiSeq platform to analyze microbial diversity, composition, and metabolic pathways using the Quantitative Insights Into Microbial Ecology 2 pipeline and R software.
Key Clinical Findings of the Study Include:
• Comparable Cohort Baselines: The study enrolled 34 active CD cases with a mean age of 40.9 ± 11.2 years (61.8% male) and 33 patients in remission with a mean age of 39.5 ± 10.2 years (60.6% male).
• Pronounced Fecal Diversity Shifts: The study showed that changes in bacterial diversity based on disease status were more prominent in stool than in mucosal tissue samples.
• Distinct Fecal Taxonomic Associations: The study identified Romboutsia, Ruminococcus, and Dorea as genera linked with active CD, while Bifidobacterium, Escherichia, and Enterococcus were associated with remission.
• Divergent Mucosal Taxonomic Signatures: The study associated Bacillus and Megasphaera with active CD, whereas Veillonella, Fusobacterium, and Bifidobacterium species characterized mucosal remission.
• Prominent Mucosal Functional Disparity: The study revealed that several predicted metabolic pathways showed significant differences between active CD and remission groups in mucosal bacteria, a contrast less pronounced in fecal communities.
The results suggest that the microbial community structure and predicted metabolic functions of treatment-naïve CD differ significantly from those in remission across the 67 evaluated patients. Specifically, these functional-level changes are prominently expressed in the mucosal microbiota but are not replicated in the fecal community, emphasizing the clinical value of tissue-level assessments.
Thus, the study concludes clinicians may find it highly beneficial to assess the gut microbiota, particularly through mucosal biopsies, prior to initiating therapy to bypass the confounding impacts of treatment and obtain a clearer, more accurate depiction of a patient's microbial dysbiosis.
While these findings offer valuable insights, the use of predicted functional analysis and the focused sample size of 67 participants suggest that future research with direct metagenomic sequencing in larger cohorts could further validate these mucosal-specific metabolic pathways.
Reference
Dutta, A. K., Abraham, D., Benny, B., Govindan, K., & Joseph, A. J. (2026). Gut microbiota in treatment-naïve active Crohn’s disease compared to those in remission: Divergent trends in mucosal versus fecal bacterial community. Indian Journal of Gastroenterology. Published online June 23, 2026.
