Gut microbiome can be restored without adverse events after Helicobacter pylori eradication therapy in teenagers

Objectives: The effect of Helicobacter pylori eradication on the gut microbiota of teenagers is unknown; hence, this study aimed to assess changes in the gut microbiome after H. pylori eradication therapy in teenagers. Materials and Methods: Changes in gut microbiota before and after H. pylori eradication were prospectively investigated in eight students without any underlying diseases, via next-generation sequencing of 16S rDNA. Twenty-four stool samples were collected, and operational taxonomic unit analysis was performed. As secondary analyses, alpha and beta diversity were evaluated. Furthermore, pre-treatment microbiome compositions were compared with those 1 week and 2 months after treatment. Results: Alpha diversity analysis revealed that both species richness and evenness were recovered to pre-treatment levels at 2 months after eradication therapy. Slight but non-significant differences were observed in bacterial species abundance between pre- and post-treatment samples, upon beta diversity analysis. Although the relative abundance of Bacteroidetes tended to increase and that of Actinobacteria significantly decreased immediately after eradication therapy, the taxonomic composition was similar to that before treatment and at 2 months post-eradication. However, two students showed significant changes in the gut microbiota in relative abundances at the level of the phylum, class, and order. Conclusions: Although H. pylori eradication therapy caused short-term dysbiosis, microbial diversity was restored in healthy teenagers. However, as the relative abundance of gut microbiota in some cases remained altered, the effect of H. pylori eradication therapy on the gut microbiome should be continuously monitored.