Gut Liver. 2021;15(2):253-261.

Compositional and Functional Changes in the Gut Microbiota in Irritable Bowel Syndrome Patients.

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제1저자 이선민 · 교신저자 김나영

PMID 32457278 PMC7960967 DOI 10.5009/gnl19379 IF 4.1 소화기내과

소속 (4)

Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
Digestive Disease Research Institute, Wonkwang University, Iksan, Korea.
DCNbio, Seongnam, Korea.

Abstract

BACKGROUND/AIMS This study aimed to characterize the changes in the gut microbiota of irritable bowel syndrome (IBS) patients and to investigate the consequent alterations in bacterial functions.

METHODS We performed 16S rRNA metagenomic sequencing and a phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analyses using fecal samples from control (n=12) and diarrhea-dominant IBS patients (n=7).

RESULTS The samples were clustered by the principal coordinates analysis depending on the presence of IBS (p=0.003). In the IBS patients, the abundances of Acidaminococcaceae, Sutterellaceae, and Desulfovibrionaceae were significantly increased, while those of Enterococcaceae, Leuconostocaceae, Clostridiaceae, Peptostreptococcaceae, and Lachnospiraceae were significantly decreased. The PICRUSt results indicated that two orthologues involved in secondary bile acid biosynthesis were significantly decreased in IBS patients. Modules involved in multidrug resistance, lipopolysaccharide biosynthesis, the reductive citrate cycle, and the citrate cycle were significantly increased in the IBS patients. In contrast, modules involved in cationic antimicrobial peptide resistance, and some transport systems were more abundant in controls than in IBS patients.

CONCLUSIONS Changes in the gut microbiota composition in IBS patients lead to alterations in bacterial functions, such as bile acid transformation and the induction of inflammation, which is a known pathophysiological mechanism of IBS.

Keywords

Gastrointestinal microbiomeIrritable bowel syndrome

Figures

**Fig. 1** Clustering of samples according to irritable bowel syndrome (IBS) status. Principal coordinates analysis (PCoA) of 19 samples. Control (CON) samples are indicated with black dots, and IBS samples are indicated with red dots.

**Fig. 2** Diversity indices of the gut microbiota. The indices indicating the species richness, i.e., the (A) observed operational taxonomic unit (OTU)count and (B) Chao1 indices, and those indicating the species diversity, i.e., the (C) Shannon and (D) phylogenetic diversity indices, did not differ significantly between the normal control and irritable bowel syndrome (IBS) groups. p-values were evaluated with the Wilcoxon rank sum test.

**Fig. 3** Differences in the microbiota composition between irritable bowel syndrome (IBS) samples and normal control samples. (A) Linear discriminant analysis (LDA) effect size (LEfSe) of the gut microbiota at the family level. Abundance ratios of the families that differed between the IBS and normal control groups according to LEfSe: (B) Acidaminococcaceae, (C) Sutterellaceae, (D) Desulfovibrionaceae, (E) Enterococcaceae, (F) Leuconostocaceae, (G) Clostridiaceae, (H) Peptostreptococcaceae, and (I) Lachnospiraceae. p-values were assessed with the Wilcoxon rank sum test.

**Fig. 4** Changes in orthologues involved in secondary bile acid biosynthesis (pathway ko00121). Abundance of (A) K07007 (baiN, 3-dehydro-bile acid delta 4,6-reductase) and (B) K15874 (baiI, bile acid 7 beta-dehydratase) in normal controls (n=12) and IBS patients (n=7). p-values were evaluated with the Wilcoxon rank sum test. IBS, irritable bowel syndrome.

**Fig. 5** Linear discriminant analysis (LDA) effect size of modules according to the occurrence of irritable bowel syndrome (IBS). ABC, ATP-binding cassette. *CAMP, cationic antimicrobial peptide; Ami, N-acetylmuramoyl-L-alanine amidase.

그림 출처: PubMed Central 공개 논문 (PMC7960967)

Conflict of interest statement

CONFLICTS OF INTEREST. No potential conflict of interest relevant to this article was reported.

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