Microbiological status of patients with inflammatory bowel diseases

Objective. To study the microbial composition of biopsies in inflammatory bowel diseases. Materials and Methods. From November 2019 to February 2023, 100 patients of the coloproctology department with inflammatory bowel diseases (IBD) were examined: 65 patients with ulcerative colitis and 35 patients with Crohn’s disease. A metagenomic analysis of biopsies (DNA sequencer Illumina, USA) obtained during endoscopic examination using a standard technique, with a bioiformatic data analysis, was performed. The diversity of microbiomes in the samples was assessed using the Fisher index. The similarity of microbiomes between samples (beta diversity) was estimated using the Bray–Curtis distance. The analysis of the main coordinates (PCoA) was performed to visualize the similarity of microbiomes between samples. The results were considered statistically significant at p < 0.05. Results. Metagenomic analysis made it possible to study the qualitative and quantitative composition of the intestinal microbiota in patients with ulcerative colitis and Crohn’s disease. 20 types of microorganisms were identified, including 146 families, 336 genera, 516 species of microorganisms. At the phylum level, two main ones were obtained: Proteobacteria, Firmicutes. Comparing the studied nosological forms with each other, there is an increase in the diversity of bacteria of the phylum Proteobacteria by 1.2 times in ulcerative colitis. The predominant species of this phylum is Escherichia coli. In turn, the relative abundance of E. coli is 1.6 times higher in patients with Crohn’s disease (23.9%/14.48%). Taxonomic categories that are absent in this or that type of disease have been identified – departments: Cyanobacteria (0.049%), Acidobacteria (0.010), Planctomycetes (0.009%), SR1 (0.007%), Synergistetes (0.007%), Chloroflexi (0.004%), Lentisphaerae (0.002%), OD1 (Parcubacteria) (0.001%), Spirochaetes (0.001%), Helicobacter genus (5%) were detected only in patients with ulcerative colitis; department Gemmatimonadetes (0.009%) – with Crohn’s disease. Conclusions. Identification of intestinal microorganisms associated with the pathogenesis of inflammatory bowel diseases is a critical aspect for a thorough understanding of the various pathogenic factors that are of great importance for the early detection of IBD.