Comparison of oral flora before and after triple therapy for Helicobacter pylori eradication in patient with gastric disease

The oral cavity is recognized as a major route for infection by Helicobacter pylori, which colonizes the gastric mucosa. Therapeutic options for elimination in patients with digestive disease have been established, though whether antibiotics are effective for H. pylori harbored in the oral cavity as well as oral commensal bacteria remain unknown. A 29-year-old woman visited a gastrointestinal clinic with a chief complaint of stomach ache. Gastroscopy and urine test findings for H. pylori IgG led to a definitive diagnosis of goose bumps gastritis induced by bacteria in the stomach, and triple therapy for H. pylori eradication was administered. Oral samples were obtained 10 times at a dental hospital clinic from 1 week before until 6 months after starting triple therapy. Nested PCR amplifying the ureA gene and PCR assays using species-specific primer sets were performed to detect H. pylori and major oral commensal bacterial species, respectively, in those samples. Bacterial DNA encoding the ureA gene of H. pylori in oral specimens was detected prior to starting therapy, which was then reduced during and not detected after finishing treatment. Although the populations of major oral pathogenic bacteria, such as periodontopathic and oral streptococcal species, were drastically reduced during triple therapy, most had recovered within approximately 1 week after ending treatment. These results suggest that a conventional triple therapy approach for eradication of H. pylori in cases of digestive disease is effective for elimination of the bacterium from the oral cavity. On the other hand, after finishing such therapy, the oral flora composition is not drastically changed.