Exploring The Changes Of Intestinal Flora In Crohn’s Disease Based On The Same Diet Background

Objective:Using 16S rRNA gene sequencing technology to compare the similarities and differences of the intestinal flora between CD and UC,and healthy people in Yunnan,and compare the differences in intestinal flora between CD and healthy people living with the same diet,Discover the key dysregulated flora related to CD and lay the foundation for targeted regulatory treatment.Method:A total of 156 fecal samples include 34 CD and people living with them,50 UC,and 38 healthy people were collected for 16S rDNA amplification and sequencing,and the sequencing results were analyzed for biological information.Results:1、Analysis of the composition of the microbial community structure:156 samples produced a total of 3274 OTUs.At the phylum level,Firmicutes,Bacteroidetes,Proteobacteria,and Actinobacteria is the dominant bacteria phyla.At the genus level,Escherichia-Shigella,Bacteroides,and Faecalibacterium are the dominant bacteria genus.2、Analysis of the common and unique flora of the CD group and other groups:779 OTU overlaps in the 4 groups,929 OTU overlaps in the CD group and the UC group,1130 OTU overlaps in the CD group and the CD roommate group,1177 OTU overlaps in the CD group with the healthy control group.Among them,643 OTUs are unique to CD,339 OTUs are unique to CD roommate group,605 OTUs are unique to healthy people,and 422 OTUs are unique to UC.3、Comparison of a diversity of CD patients:The observed_species,chao,and ACE indexes of the CD group were significantly larger than those of the UC group,;the shannon index of the CD group was obvious lower than that of the CD roommate group and healthy control group,The simpson index of the CD group was significantly lower than that of the CD roommate group.4、Comparison of β diversity of CD patients:There are significant differences in the microbial community structure between the CD group and other groups.The difference between CD and UC is smaller than the difference between CD and healthy people or CD roommate group.There are differences between healthy control group and CD roommate group,but the difference is not statistically significant.4.1:Comparison of the differences in flora between CD and UC:There is no significant difference at the phylum level;at the family level,compared to the UC group,the CD group have the significant increase floras are Lachnospiraceae and Leuconostocaceae,the significant decrease floras are Bifidobacteriaceae,Veillonellaceae,Burkholderiaceae,and Carnobacteriaceae;at the genus level,compared to the UC group,the CD group have the significant increase floras are Blautia、Eubacterium hallii group、Anaerostipes,the significant decrease floras are the Bifidobacterium,Megamonas,and Veillonella.4.2:Comparison of the differences in flora between CD and CD roommate group、healthy control group:At the phylum level,in the CD group,the Proteobacteria increased significantly,and the Firmicutes decreased significantly.At the family level,compared with the CD roommate group,in the CD group,the significantly increased Floras are Enterococcaceae,Enterobacteriaceae,and Streptococcaceae,the significantly decreased Floras are Ruminococcaceae、Peptostreptococcaceae,Clostridiaceae₁、Rikenellaceae、Christensenellaceae.Compared with the healthy control group,in the CD group,Enterobacteriaceae is the significant increase flora,and the significant decrease floras are Lachnospiraceae and Christensenellaceae;at the genus level,compared with the CD roommate group,in the CD group,the significantly increased Floras are Enterococcus,Escherichia-Shigella,and Streptococcus.compared with the healthy control group,in the CD group,the significantly increased Floras are Escherichia-Shigella,while the CD roommate group and healthy control group have several floras increased.4.3:Comparison of the differences in flora between the CD roommate group and the healthy control group:There was no significant difference at the phylum level;at the family level,Compared with the healthy control group,the CD roommate group have a significant increase flora is Veillonellaceae.the decrease one is Streptococcaceae;at the genus level,the CD roommate group has more Faecalibacterium and Alistipes than the healthy control group,while the health control group has more Streptococcus than CD roommate group.5、LEfSe:The classification of the intestinal flora in the CD group which is significantly higher and has clinical significance is Bacilli→Lactobacillales→Streptococcaceae,but compared with CD roommate group,in the CD group,the significantly lower and has clinical significance flora are Clostridia→Clostridiales→Ruminococcaceae,Peptostreptococcaceae、Clostridiaceae.Compared with healthy control group,in the CD group,the significantly lower and has clinical significance flora are Lachnospiraceae、Alphaproteobacteria→Sphingomonadales→Sphingomonadaceae.Compared with UC group,in the CD group,the significantly lower and has clinical significance flora are Anctinobacteria→Bifidobacteriales→Bifidobacteriaceae、Negativicutes→Selenomonadales→Veillonellaceae.Conclusions:1、The dysbiosis of IBD is most related to the changes of Fimicutes and Proteobacteria;2、After controlling dietary confounding factors,it is found that the CD is significantly increased than healthy people is Enterobacteriaceae→Escherichia-Shigella-*Escherichia coli,and the significantly reduced is Christensenellaceae,thereinto Christensenellaceae has the potential to become an important microbial target for improving the CD patients’ long-term diarrhea;at the genus level,the Dorea and Lachnospiraceae NK4A136 group seem to have an antagonistic effect on the Clostridium difficile infection in CD.3、When comparing CD and UC,we found some flora changes which were rarely found in previous studies.In CD,there are more Terrisporobacter,less Parasutterella than UC.These differences may become the new non-invasive biological markers between CD and UC;thereinto Terrisporobacter may provide clues for monitoring the inflammation in CD.4、The LEfSe analysis indicated that the loss of beneficial bacteria in CD is more serious than the increase in harmful bacteria.