Characteristics Of Gastric Microecology In Patients With Chronic Gastritis

Objective Helicobacter pylori infection is the main cause of chronic gastritis,but the role of non-helicobacter pylori gastric microbiota in the occurrence of chronic gastritis remains unclear.The purpose of this study was to analyze the characteristics and functions of gastric microecology in patients with chronic gastritis with different endoscopic manifestations,pathological diagnosis and helicobacter pylori infection status.Methods A total of 75 patients with chronic gastritis diagnosed by gastroscopy in the Third Affiliated Hospital of Anhui Medical University from October 2020 to April 2021 were included in this study.According to the endoscopic diagnosis（atrophic gastritis,erosive gastritis,patchy erosive gastritis,sheet,strip erosive gastritis,erosive gastritis uplift erosive gastritis,pitting erosion sex gastritis,scattered in the sexual erosive gastritis flat uplift,proliferative gastritis）and pathological diagnosis,erosive gastritis,chronic superficial gastritis,atrophic gastritis and intestinal metaplasia,intraepithelial neoplasia,hyperplastic polyp)Group.In this study,16SrRNA high-throughput gene sequencing was used to analyze the gastric microbial species in gastric mucosal tissues.The diversity of α was analyzed at phylum,class,order,family,genus and species levels.The Observed-species Index and Chao1 Index reflected the abundance of gastric mucosa tissue flora,while Shannon Index and Simpson Index reflected the diversity of gastric mucosa tissue flora.Linear discriminant analysis effect size method was used to evaluate the difference of microbial composition in each group of patients with chronic gastritis,and PICRUSt was used to obtain the predictive functional map of gastric microbial community.Chi-square test and T test were used for statistical analysis.Results A total of 87 phyla were identified in all stomach biopsy samples from 75 patients with chronic gastritis.For the α diversity analysis of chronic gastritis with different endoscopic manifestations,the p values of Observed-species Index between atrophy and strip erosion,strip erosion and hyperplasia,strip erosion and strip erosion were 0.0131,0.0156,0.0175,etc.,the differences were statistically significant（P<0.05）.There were statistically significant differences in Shannon Index between atrophy and strip erosion,strip erosion and uplift erosion,flake erosion and strip erosion（P<0.05）,with significant P values of 0.0134,0.0171 and 0.0317.β diversity analysis showed that there was significant difference in the composition of the bacteria between atrophy and flake erosion chronic gastritis patients（ADONIS R=0.084,P=0.034）,and the NMDS stress value was less than 0.2（stress=0.116）.The sparse curve and Rank Abundance curve of different pathological diagnosis of chronic gastritis showed the highest Abundance and homogeneity of pathological tissue types of hyperplastic polyps with high bacterial diversity.Species abundance and evenness decreased gradually from atrophy,intestinal metaplasia to intraepithelial neoplasia.The species abundance and evenness were the lowest in superficial gastritis group.Venn plots based on OTU level analysis showed that species abundance in the Hp-negative group with fewer cases was higher than that in the Hp-positive group.At phyla level,firmicutes had the highest abundance in Hp negative group,followed by Bacteroidetes,while Campylobacter had the highest abundance in Hp positive group,followed by Firmicutes.At the species level,Clostridium tender was dominant in Hp negative group and Helicobacter pylori was dominant in Hp positive group.Based on the random forest analysis at the species level,the AUC value obtained by comparing the ROC curve between atrophy and patchy erosion of chronic gastritis with different endoscopic manifestations was 0.8688.In the cases of intestinal metaplasia and superficial gastritis,erosive gastritis and intestinal metaplasia,erosive gastritis and superficial gastritis in different pathological tissues,the AUC values obtained by ROC curve analysis in this study were 0.9318,0.9300 and 0.9500,respectively.Conclusion Based on the detailed analysis of gastric microflora in patients with chronic gastritis,it was found that the abundance and composition of gastric microflora varied with different endoscopic manifestations,pathological diagnosis and helicobacter pylori infection.The change pattern of gastric microflora composition and function was a high indicator of the occurrence and development of chronic gastritis.