Study On The Composition And Functional Prediction Of Intestinal Microbiome In Patients With Inflammatory Bowel Disease

Background: The cause of inflammatory bowel disease(IBD)is unknown.In recent years,the study of intestinal microbiota in patients with IBD has attracted great attention.However,the results of studies on intestinal microbiota in patients with IBD were inconsistent.In addition,there have been many studies on the composition of intestinal microbiota in IBD,and few studies on the function of intestinal microbiome.Objective:In this study,the composition of faecal microbiota in patients with IBD was analyzed,and the function of the microflora was predicted to explore the mechanism of the influence of intestinal flora on IBD.Methods:Qualified patients with IBD and healthy controls(HC)matched for gender and age were recruited from the first affiliated hospital of guangxi medical university,and fresh stool samples were collected from all the subjects.The total DNA of stool samples was extracted with the E.Z.N.A.(?) soil kit.The v3-v4 hypervariable region of the 16 s rRNA gene of the sample bacteria was amplified by PCR technology,and then the recovered and purified PCR amplification products were sequenced by Miseq PE300 platform.Then the microbial composition and 16 s gene function prediction analysis were performed on the Isanger biocloud platform.The composition and function differences of microbiota between IBD and HC group,different types of inflammatory bowel disease(including ulcerative colitis and Crohn’s disease)and HC group,and between different types in IBD group was analyzed.Results:(1)Stool samples of this study were collected from 20 patients with crohn’s disease(CD),10 patients with ulcerative colitis(UC),and 30 healthy controls.(2)Results of 16 s rRNA sequencing showed that there was no significant difference in the α diversity between the inflammatory bowel disease group and the healthy control group(P >0.05),however the α diversity in the healthy control group was significantly higher than that in the crohn’s disease group(P = 0.027).(3)Principal coordinate analysis(PCo A)showed that there was significant difference between the IBD and the HC group(P < 0.01),Moreover,the difference in the diversity of patients with IBD was also statistically significant among different types(P<0.01).(4)Compared with the healthy subjects,the bacterial structure and composition of IBD group were disordered.At the phylum level,the abundance of Proteobacteria was significantly enriched in IBD(P=0.001),whereas the abundance of Epsilonbacteraeota in the HC was significantly higher than that in IBD group(P=0.004).In addition,the abundance of Acidobacteria in UC was significantly higher than that in HC group(P=0.010)and CD group(P =0.044).(5)At the class level,the abundance of Gammaproteobacteria in IBD was significantly higher than that in the HC group(P< 0.001),The abundance of Campylobacteria in UC group was significantly higher than that in healthy control group(P=0.024).(6)At the order level,Betaproteobacteriales(P=0.001)and Enterobacteriales(P=0.022)were significantly increased in the IBD compared to HC group.The Sneathiellales abundance in the CD group was significantly higher than that in the HC group(P=0.017),and the Caulobacterales abundance in the ulcerative colitis group was significantly higher than that in HC(P=0.012)and the CD group(P=0.026).(7)At the family level,compared with the HC group,the abundance of Bacteroidaceae(P=0.025)and Berkheniaceae(P=0.001)in the CD group was significantly increased,and the abundance of Enterobacteriaceae in the UC group was significantly increased(P=0.031).(8)At the genus level,compared with the IBD,the abundance of Megamonas(P=0.004),Lachnospira(P<0.001)and Ruminococcus]＿torques＿group(P=0.018)in the HC was significantly increased,and the abundance of Escherichia-shigella in HC was significantly decreased(P=0.006).The abundance of Megasphaera(P=0.044),Ralatonia(P=0.049)and Bacteroidetes(P=0.025)in CD was significantly higher than that in HC group(P = 0.031),and the abundance of Enterococcus in UC was significantly higher than that in HC.(9)Genetic information processing and immune system pathway were significantly enriched in HC,while valine,leucine and isoleucine biosynthesis pathway and primary bile acid biosynthesis were significantly enriched in IBD group(P < 0.05).The levels of biosynthesis pathway of primary bile acid and secondary bile acid in CD group were significantly higher than those in healthy control group(P < 0.05).In addition,the level of sphingomyelin metabolism pathway in CD group was significantly higher than that in HC and UC group(P < 0.05).Conclusions:Compared with the healthy control group,there were more pathogenic bacteria and fewer potentially beneficial bacteria in the intestinal microbiota of patients with inflammatory bowel disease.Meanwhile,the amino acid biosynthesis pathway,sphingomyelin metabolism pathway,primary bile acid and secondary bile acid biosynthesis pathway were changed in the disease group.