Characteristics Of Intestinal Micrbiota Of Colorectal Laterally Spreading Tumors

Objective: To investigate the characteristics of intestinal microbiota of colorectal lateral spreading tumors.Methods: The subjects who underwent colonoscopy at Renji Hospital affiliated to Shanghai Jiao Tong University School of Medicine from August2017 to December 2018 were enrolled.They were divided into healthy control(HC)group,colorectal adenoma(CRA)group and lateral spreading tumor(LST)group.We collected the fecal samples before colonoscopy and the intestinal mucosa specimens during colonoscopy.Fecal and tissue genomic DNA was subjected to high-throughput sequencing of Illumina Miseq in the V3-V4 region of the 16 S r DNA gene to analyze the characteristics of the intestinal microbiota of the lateral spreading tumors,and the sequencing results were verified by real-time fluorescent quantitative PCR.Results: The main intestinal phylums of the three groups were Firmicutes,Bacteroides,Proteobacteria and Actinomycetes.The abundance of Proteobacteria and Actinomycetes in the LST group was relatively high,and the Bacteroides,Escherichia-Shigella,Blautia,Lactobacillus,Streptococcus and Prevolla were the main genuses.Linear discriminant analysis revealed that Lactobacillus salivarius,Intestinibacter bartlettii DSM16795,and Clostridium sp AT5 were specific bacteria in the LST fecal samples.In the mucosal samples,Lactobacillus johnsonii,Bacteroides fragilis,Streptococcus salivarius subsp.salivarius,Pediococcus pentosaceus,and Sphingopyxis granuli were LST specific flora.The results of real-time fluorescent quantitative PCR showed that the abundance of enterotoxigenic Bacteroides fragilis in LST group was significantly higher than that in HC group and CRA group.LSTs located in left colon and rectum possessed higher abundance of enterotoxigenic Bacteroides fragilis than that in right colon.Moreover,LST with non-granular pseudo-depressed type and LST with granular nodular mixed type showed higher abundance of enterotoxigenic Bacteroides fragilis than that of LST with non-granular flatelevated type and LST with granular homogeneous type.The abundance of enterotoxigenic Bacteroides fragilis in advanced LSTs was higher in abundance than non-advanced LSTs.Conclusion: The intestinal flora composition of LSTs was different from that of HC group and CRA group.And the enterotoxigenic Bacteroides fragilis may be important for the developmental of LSTs.