Metagenomics of Fecal Gut Microbiota in Common Traditional Chinese Medicine Syndrome Types of Irritable Bowel Syndrome with Diarrhea：A Cross-sectional Study / 中医杂志

ABSTRACT

ObjectiveTo investigate the structural and functional characteristics of gut microbiota in common traditional Chinese medicine （TCM） syndromes of irritable bowel syndrome with diarrhea （IBS-D）. MethodsIBS-D patients who visited the Hospital of Chengdu University of Traditional Chinese Medicine， and healthy participants from the Physical Examination Centre of the same hospital were recruited from 1st January 2020 to 31st March 2021.The IBS-D patients were classified into syndrome of liver constraint and spleen deficiency， and syndrome of spleen deficiency and dampness exuberance； together with the recruited healthy participants， there were liver-constraint group， dampness-exuberance group， and healthy group. General information， including age， gender and body mass index （BMI）， were collected， and Irritable Bowel Syndrome Symptom Severity Scale （IBS-SSS） as well as Irritable Bowel Syndrome Quality of Life Scale （IBS-QOL） scores were additionally collected from IBS-D patients. Fresh fecal samples were also collected and tested by macro-genome sequencing technology for abundance statistical display， PCoA， Anosim， LEfSe bioinformatic analysis of the annotated gut microbiota structure and function. ResultsThere was no statistically significant difference in the general information of the participants in the three groups （P＞0.05）； the difference in the IBS-SSS and IBS-QOL scores between liver-constraint group and dampness-exuberance group were not statistically significant （P＞0.05）. The study included 28 cases each in liver-constraint group， dampness-exuberance group， and healthy group. The number of specific genes to patients in liver-constraint group was 269 135， with 216 156 in dampness-exuberance group and 249 759 in healthy group， accounting of total 1 784 036 in the three groups. There were differences in the relative abundance distribution of the top ten species of gut microbiota among the three groups， with smaller differences at the phylum， class and order levels， and larger differences at the family， genus and species levels. There were differences in the relative abundance of structure and function of the gut microbiota among the three groups. Species PCoA and Anosim analyses at the species level showed significant differences in the composition of the microbiota among the three groups. Further LEfSe analyses showed that patients in liver-constraint group were screened for 14 dominant strains， of which Clostridium sp. CAG 217， Lachnospira pectinoschiza， Anaerotruncus sp. CAG 528， Paeniclostridium sordellii， Eubecterium sp. CAG 76， Bacillus cereus were affected to a greater extent in abundance differences； dampness-exuberance group screened 24 species of dominant bacteria， of which Roseburia inulinivorans， Eubacterium sp. CAG 251， Roseburia hominis， Unclassified Eubacterium rectale， Roseburia intestinalis， and Megamonas funiformis were affected to a greater extent in abundance differences； no dominant functional genes were screened for patients in liver-constraint group， and dampness-exuberance group was screened for flagellum assembly （ko02040）， porphyrin metabolism （ ko00860）， salmonella infection （ko05132）， and benzoic acid degradation （ko00362）. The differentially dominant functional genes in liver-constraint group and dampness-exuberance group may mainly focus on metabolism （including biodegradation and metabolism of exogenous substances， energy metabolism， lipid metabolism， etc.）. ConclusionIBS-D with syndrome of liver constraint and spleen deficiency is characterized by the enrichment of 14 gut microbiota， such as Clostridium sp. CAG 217， while IBS-D with syndrome of spleen deficiency and dampness exuberance is characterized by the enrichment of 24 gut microbiota， such as Roseburia inulinivorans， and 4 functional enrichments， such as flagellum assembly. Clostridium sp. CAG 217 and Roseburia inulinivorans are expected to be biomarkers for IBS-D patients in the two syndromes， respectively.