Does Helicobacter pylori infection affect the structure of bacteria in the gastric mucosa and fluid in patients with chronic antral gastritis?

This study aimed to evaluate the composition of the gastric microbiota in the gastric mucosa and gastric fluid of patients with chronic antral gastritis. Specifically, we sought to determine whether Helicobacter pylori (Hp) infection changes the bacterial community in the gastric mucosa or alters the microbiota in the gastric fluid. The bacterial community at another site in the stomach was also investigated. DNA was extracted from 160 samples collected from 40 patients with chronic antral gastritis (20 Hp-positive and 20 Hp-negative cases). Three tissue samples of the gastric mucosa (gastric angle, body, and antral mucosa) and one tube of gastric fluid were collected from every patient. A 16S rRNA amplification library was created, and high-throughput sequencing was performed. A profile of the community composition was obtained using bioinformatics methods, including cluster, taxonomy, and diversity analyses. Analysis of the gastric bacterial community revealed that the community compositions of the gastric mucosa and gastric fluid of patients without Hp are similar to but show differences from those of Hp-positive patients. The microbiota in Hp-positive patients exhibited reduced microbial diversity, and the gastric fluid of these patients contained a small proportion of Hp. The richness of Leptotrichia in mucosal samples was greater than that in gastric fluid samples from Hp-negative patients with chronic antral gastritis. Hp changes the growth of other microbiota in the mucosa and affects the microbiota in the gastric fluid of patients with chronic antral gastritis. In addition to Hp, the presence of other bacteria might be related to the development of chronic antral gastritis.