Gastric microbes associated with gastric inflammation, atrophy and intestinal metaplasia 1 year after eradication.

OBJECTIVE

is associated with gastric inflammation, precancerous gastric atrophy (GA) and intestinal metaplasia (IM). We aimed to identify microbes that are associated with progressive inflammation, GA and IM 1 year after eradication.

DESIGN

A total of 587 -positive patients were randomised to receive eradication therapy (295 patients) or placebo (292 patients). Bacterial taxonomy was analysed on 404 gastric biopsy samples comprising 102 pairs before and after 1 year eradication and 100 pairs before and after 1 year placebo by 16S rRNA sequencing.

RESULTS

Analysis of microbial sequences confirmed the eradication of in treated group after 1 year. Principal component analysis revealed distinct microbial clusters reflected by increase in bacterial diversity (p<0.00001) after eradication. While microbial interactions remained largely unchanged after placebo treatment, microbial co-occurrence was less in treated group. , and were enriched while and were depleted in patients with persistent inflammation 1 year after eradication. A distinct cluster of oral bacteria comprising , , , and were associated with emergence and persistence of GA and IM. Probiotic was depleted in subjects who developed GA following eradication. Functional pathways including amino acid metabolism and inositol phosphate metabolism were enriched while folate biosynthesis and NOD-like receptor signalling decreased in atrophy/IM-associated gastric microbiota.

CONCLUSION

This study identified that gastric microbes contribute to the progression of gastric carcinogenesis after eradication.

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