Compositional changes in fecal microbiota associated with clinical phenotypes and prognosis in Korean patients with inflammatory bowel disease Original paper

What was studied?

The study examined fecal microbiota in IBD to determine how microbial composition differs between Korean patients with ulcerative colitis (UC), Crohn’s disease (CD), and healthy controls, and whether specific taxa function as biomarkers for disease severity, extent, and prognosis ir-2021-00168. Researchers used 16S rRNA gene sequencing of stool samples to characterize microbial diversity, identify taxonomic shifts, and link these profiles to clinical phenotypes. Analyses included alpha- and beta-diversity metrics, relative abundance comparisons, and linear discriminant analysis to pinpoint microbial signatures. Particular attention was given to taxa enriched or depleted in relation to inflammation severity, anatomical disease distribution, and long-term clinical outcomes. The work also explored whether distinct microbial signatures could help clinicians classify IBD phenotypes more accurately and predict therapeutic trajectories.

Who was studied?

The study included 70 UC patients, 39 CD patients, and 100 healthy controls recruited across three academic hospitals in Korea ir-2021-00168. Disease severity in UC was graded via the Mayo score, while CD severity followed the Crohn’s Disease Activity Index. Participants had no recent exposure to probiotics or antibiotics, minimizing confounding effects on microbial composition. Healthy controls were drawn from community cohorts without gastrointestinal symptoms. UC patients were further categorized by disease extent (proctitis, left-sided colitis, or extensive colitis), and CD patients by ileal, colonic, or ileocolonic involvement. Prognostic groups were defined based on whether participants later required biologic therapy or surgery during an average eight-year follow-up.

Most important findings

The study confirmed profound dysbiosis in both UC and CD. Alpha-diversity decreased significantly in IBD and was lowest in CD, which also showed the greatest compositional deviation from healthy controls, as illustrated in the phylum-level bar plots on page 6 showing marked Proteobacteria expansion. CD exhibited striking enrichment of Escherichia coli (≈11%) compared with UC and healthy controls (≈2%). UC patients showed progressive loss of richness as severity and extent worsened, with distinct microbial shifts between proctitis and extensive colitis (page 5).

Several key taxa emerged as phenotype markers:

• UC severity biomarkers included Lactobacillus salivarius, Clostridioides difficile, Intestinibacter bartlettii, Weissella confusa, and Anaerostipes hadrus.
• UC extent biomarkers included Bifidobacterium bifidum, I. bartlettii, Flavonifractor plautii, Ruminococcus gnavus, and Lactobacillus paracasei.
• CD activity biomarkers included Phascolarctobacterium succinatutens, L. salivarius, L. mucosae, Porphyromonas asaccharolytica, and Coprococcus catus.
• CD location biomarkers included the L. gasseri group, Bacteroides ovatus, and W. confusa.

Prognostically, CD patients with better outcomes showed higher abundances of Lachnospiraceae and R. gnavus (page 8), an intriguing combination given their contrasting inflammatory associations.

Key implications

Microbiome profiling in IBD can meaningfully discriminate disease phenotypes, offering a noninvasive complement to endoscopy. The discovery of taxa associated with severity, extent, and prognosis suggests that microbial biomarkers may support early risk stratification and individualized therapy design. Species-level signatures, particularly expansions of Proteobacteria in CD and diverse lactic acid–producing taxa in severe UC, highlight microbial pathways that may be leveraged for targeted interventions or monitored longitudinally to assess treatment response.

Citation

Shin SY, Kim Y, Kim WS, et al. Compositional changes in fecal microbiota associated with clinical phenotypes and prognosis in Korean patients with inflammatory bowel disease. Intest Res. 2023;21(1):148-160. doi:10.5217/ir.2021.00168.

Overview

• Excerpt (≤50 words): This study analyzed fecal microbiota in Korean IBD patients, identifying species-level biomarkers linked to disease severity, extent, and prognosis, with major microbial shifts distinguishing UC, CD, and healthy individuals.
• Google meta description (≤130 characters): Fecal microbiota in IBD reveals biomarkers tied to disease severity, extent, and prognosis.

SEO Information

• Focus Keyphrase: fecal microbiota in IBD
• Slug: fecal-microbiota-in-ibd
• SEO Title: Fecal Microbiota in IBD and Its Biomarker Associations