Intestinal and fecal microbiome in patients with ulcerative colitis

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To study mucosal and fecal microbiota in patients with ulcerative colitis (UC) in the Russian population.

Material and methods

Seventy patients with UC (43 females and 27 males, mean age of 40±14.4 years) were enrolled in this study. The average duration of the disease was 7.3±6.9 years. Extensive colitis was diagnosed in 55 (78.6%) patients and left-sided colitis in 15 (21.4%) patients. Three (4.3%) patients presented with acute UC, 29 (41.4%) patients with relapsing course of the disease and 38 (54.3%) patients with remitting course. The endoscopic activity of UC was evaluated by Schroeder classification. Eighteen patients (25.7%) had inactive disease, whereas 31 (44.3%), 18 (25.7%) and 3 (4.3%) patients showed mild, moderate and severe activity, respectively. Microbiota composition was determined in mucosal biopsies and fecal samples by real-time polymerase chain reaction (PCR) in all patients with UC and 50 non-IBD (inflammatory bowel disease) patients.


Three phylum of bacteria, that is, Firmicutes, Bacteroidetes, and Proteobacteria, predominated in the mucosal and fecal microbiota in UC patients. Mucosal and fecal microbiota composition differed slightly. In the microbiota of UC patients, compared with non-IBD patients’ group, Bacteroides significantly predominated and can be considered as biomarkers in biopsy and fecal samples. In left-sided UC, no significant difference was found between inflamed and not inflamed tissue samples (p>0.05). No statistical difference in mucosal microbiome was observed between patients with remitting or relapsing course of the disease (p>0.05). In patients with a higher endoscopic activity of UC, there was an increase in Bacteroides spp. count and decrease in Erysipelotrichaceae count (p<0.05).


Our findings suggest that the representatives of Bacteroides spp., both in biopsies and in fecal samples, can be considered as a biomarker of ulcerative colitis.

Key words

Keywords. Ulcerative colitis, microbiota, microbiome, real-time polymerase chain reaction.