FEATURES OF THE INTESTINAL MICROBIOTA COMPOSITION IN ADOLESCENTS WITH CONSTIPATION TYPE OF IRRITABLE BOWEL SYNDROME FEATURES OF THE COMPOSITION OF THE INTESTINAL

Purpose: to study the peculiarities of the intestinal microbiota composition in adolescents with constipation type of irritable bowel syndrome.Material and methods. Clinical observations and examinations of 167 children aged 10 to 17 years (79 boys, 88 girls, mean age12,7±1,6) with a verified diagnosis of irritable bowel syndrome (IBS) were carried out on the basis of the Republican Children'sClinical Hospital (consultative diagnostic clinic), Ufa.In accordance with Rome IV criteria, using the Bristol Stool Type Scale, patients were randomized into groups, taking into account the clinical form of IBS. The study of the composition of the intestinal microbiota was carried out by DNA sequencing of the hypervariable regions of the 16S rRNA gene. Bacterial DNA was isolated from 44 fecal samples (which included 15 samples fromthe comparison group, 17 from the IBS-D group and 12 from the IBS-C group). From special research methods of instrumental diagnostics to determine methane in exhaled air, all children underwent a breath test using Gastro Check test systems.Results and discussion. The obtained methane breath test data for different types of IBS demonstrated significant differences (p<0,001) when compared in both groups with IBS and the control group. In all three groups, the limit of permissible CH4 concentrations (0-200 ppm) was not exceeded, but in the IBS-C group there was a significant (p<0,001) increase in the level of methane in the exhaled air 67 (52-79) ppm, compared with the control group 9 (2-17) ppm and IBS-D group 29 (18-37) ppm. At the phylum level, the analysis of 454-pyrosequencing showed that the human fecal microbiota with IBS-C contains more Proteobacteria than the control group. There is also an increased content of Archaea, in particular Euryarchaeota, Thermoproteales, Ferroglobus.Conclusions. The predominant microorganisms in adolescents with constipation type IBS were methanogenic archaeobacteria responsible for the excessive production of methane detected during breath tests.

irritable bowel syndrome, DNA sequencing, 16Sp RNA, methanogens, constipation

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