Changes in Gastric Corpus Microbiota With Age and After Helicobacter pylori Eradication: A Long-Term Follow-Up Study

Abstract

Helicobacter pylori infection changes gastric microbiota profiles. However, it is not clear whether H. pylori eradication can restore the healthy gastric microbiota. Moreover, there has been no study regarding the changes in gastric microbiota with aging. The objective of this study was to investigate the changes in gastric corpus microbiota with age and following H. pylori eradication. Changes in corpus mucosa-associated microbiota were evaluated in 43 individuals with endoscopic follow-up > 1 year, including 8 H. pylori-uninfected and 15 H. pylori-infected subjects with no atrophy/metaplasia by histology and pepsinogen I/II ratio > 4.0; 17 H. pylori-infected subjects with atrophy/metaplasia and pepsinogen I/II ratio < 2.5; and 3 subjects with atrophy/metaplasia, no evidence of active H. pylori infection, negative for anti-H. pylori immunoglobulin G (IgG) antibody testing, and no previous history of H. pylori eradication. Successful H. pylori eradication was achieved in 21 patients. The gastric microbiota was characterized using an Illumina MiSeq platform targeting 16S ribosomal DNA (rDNA). The mean follow-up duration was 57.4 months (range, 12-145 months), and median follow-up visit was 1 (range, 1-3). Relative abundance of Lactobacillales and Streptococcus was increased with atrophy/metaplasia. In H. pylori-uninfected subjects (n = 8), an increase in Proteobacteria (Enhydrobacter, Comamonadaceae, Sphingobium); a decrease in Firmicutes (Streptococcus, Veillonella), Fusobacteria (Fusobacterium), Nocardioidaceae, Rothia, and Prevotella; and a decrease in microbial diversity were observed during the follow-up (p trend < 0.05). In 10 of 21 subjects (47.6%), H. pylori eradication induced restoration of microbial diversity; however, a predominance of Acinetobacter with a decrease in microbial diversity occurred in 11 subjects (52.3%). The presence of atrophy/metaplasia at baseline and higher neutrophil infiltration in the corpus were associated with the restoration of gastric microbiota after successful eradication, whereas a higher relative abundance of Acinetobacter at baseline was associated with the predominance of Acinetobacter after H. pylori eradication (p < 0.05). To conclude, in H. pylori-uninfected stomach, relative abundance of Proteobacteria increases, relative abundance of Firmicutes and Fusobacteria decreases, and microbial diversity decreases with aging. H. pylori eradication does not always restore gastric microbiota; in some individuals, gastric colonization by Acinetobacter species occurs after anti-Helicobacter treatment.

Keywords: Helicobacter pylori; atrophic gastritis; eradication; gastric microbiota; intestinal metaplasia.

FIGURE 1

Microbiota composition at gastric corpus mucosae according to Helicobacter pylori infection and the presence of atrophy/metaplasia. H. pylori infection decreased the microbial diversity at corpus (A,B groups 2 and 3). Compared with group 1 (H. pylori-uninfected individuals), H. pylori predominates in the gastric corpus microbiota in groups 2 and 3 (H. pylori-infected subjects), and relative abundance of Firmicutes was increased in group 4 (C H. pylori-negative subjects with atrophy/metaplasia). (D) Principal coordinates analysis showed that the study subjects can be clearly discriminated by H. pylori infection status (groups 1 and 4 vs. groups 2 and 3) but not by the presence or absence of atrophy/metaplasia. The four groups were significantly different (Bray–Curtis, unweighted, PERMANOVA p < 0.001). Group 1: H. pylori-uninfected subjects without evidence of atrophic gastritis and intestinal metaplasia by histology, pepsinogen I/II ratio ≥ 4.0, and no history of H. pylori eradication (n = 8); group 2: H. pylori-infected patients without mucosal atrophy and metaplasia by histology with pepsinogen I/II ratio > 4.0 (n = 15); group 3: H. pylori-infected patients with atrophic gastritis and/or intestinal metaplasia by histology and pepsinogen I/II ratio < 2.5 (n = 17); group 4: the patients with atrophy/metaplasia, no evidence of active H. pylori infection, negative for anti-H. pylori IgG antibody test, and no previous history of H. pylori eradication (n = 3). Hp, Helicobacter pylori.

FIGURE 2

Summary of the linear discriminant analysis (LEfSe) comparing group 2 with group 3. (A) LDA scores and (B) cladogram show significantly different taxa [p < 0.05 and Log₁₀ (LDA score) > 3.0]. Among H. pylori-positive patients (n = 32), relative abundance of Firmicutes, especially Streptococcus and Lactobacillales, was significantly increased in group 3 compared with that in group 2. Group 2: H. pylori-infected patients without mucosal atrophy and metaplasia by histology with pepsinogen I/II ratio > 4.0 (n = 15); group 3: H. pylori-infected patients with atrophic gastritis and/or intestinal metaplasia by histology and pepsinogen I/II ratio < 2.5 (n = 17).

FIGURE 3

Follow-up of the H. pylori-negative/non-atrophy subjects (n = 8). At phylum level, an increase in (A) Proteobacteria abundance and a decrease in (B) Firmicutes and (C) Fusobacteria abundance were observed during the follow-up. In addition, a decrease in α-diversity indices (number of observed OTUs and Shannon index are presented in panel D and E, respectively) were observed. OTUs, operational taxonomy units.

FIGURE 4

Changes in gastric microbiota after H. pylori eradication. H. pylori eradication led to an (A,B) increase in microbial diversity and a (C) restoration of gastric microbiota. After H. pylori eradication, two district clusters can be identified (D eradicated without Acinetobacter predominance vs. eradicated with Acinetobacter predominance). (E–G) In the eradicated without Acinetobacter predominance group (n = 10), eradication of H. pylori led to a restoration of diverse gastric microbiota composition. (H–J) However, in the eradicated with Acinetobacter predominance group (n = 11), severe dysbiosis with an increase in Acinetobacter species abundance and a decrease in microbial diversity was observed.