A Preliminary Study On The Association Between Intestinal Flora Distribution And Pancreatic Diseases Using High-throughput Sequencing Of 16S RRNA

Objective: The purpose of this study is to investigate the distribution and the characteristics of intestinal microbial flora of the patients with pancreatic diseases such as pancreatitis,pancreatic cancer,and to evaluate the correlation between its characteristics and pancreatic diseases,thus to provide a new theoretical basis for the clinical diagnosis of pancreatic diseases.Method: 80 patients diagnosed with pancreatic diseases at the department of hepatobiliary and pancreatic surgery,the second Xiangya hospital of Central South University,from January 2019 to December2019 were selected as the observation group.38 healthy volunteers from medical examination center were randomly selected as the contrast group.Illumina Miseq sequencing system was used to sequence V3-V4 hypervariable region of 16 S rRNA of intestinal microorganisms.Results: The diversity of microbial flora in intestinal microenvironment of patients was found in the result of high throughput gene sequencing.The bioinformatic analysis showed that at the level of phylum,the top five dominated phylums were Firmicutes,Bacteroidetes,Proteobacteria,Actinobacteria,Fusobacteria,respectively.At the level of class,the top five classes in relative abundance were Clostridia,Bacteroidia,Gammaproteobacteria,Bacilli,Erysipelotrichia.At the level of family,the top ten were Lachnospiraceae,Bacteroidaceae,Ruminococcaceae,Veillonellaceae,Enterobacteriaceae,Prevotellaceae,Streptococcaceae,Erysipelotrichaceae,Clostridiaceae and an unidentified type.At the level of genus,the top ones were respectively Bacteroides,Faecalibaterium,Roseburia,Escherichia,Prevotella,Megamonas,Streptococcus,Ruminococcus and an unidentified type.It has been demonstrated that the distribution of the microbial flora is correlated to the pancreatic diseases.At the level of phylum,the abundance of Proteobateria was significantly higher in the normal group,whereas the abundances of Fusobacria were significantly higher in the Pancreatitis group and the Pancreatic cancer group.At the level of class,β-Proteobacteria had a higher relative abundance in the normal group,whereas Clostridia and Baclli topped the others both in the Pancreatitis group and the Pancreatic cancer group.In addition,TM7 showed a significantly higher relative abundance than the others in the Pancreatitis group.At the level of family,Burkholderiales had a significantly higher relative abundance in the normal group.Meanwhile,Veillonellaceae and Clostridiaceae indicated a higher relative abundance in the Pancreatitis group,as Ruminococcaceae and Lachnospiraceae in the Pancreatic cancer group.Conclusions: 1.In this study,the Illumina Miseq sequencing platform and bioinformatics methods were used to analyze the distribution and relative abundance of gut microbiota of the patients with pancreatitis and pancreatic cancer.2.Compared with the normal controls,the intestinal flora in the pancreatitis group and the pancreatic cancer group were significantly different at the levels of phylum,class and family.At the same time,there were significant differences in intestinal flora between the pancreatitis group and the pancreatic cancer group.The results of this study suggest that the community characteristics and relative abundance of gut microbiota may be associated with pancreatitis and pancreatic cancer.