Influence of oral Helicobacter pylori on the success of eradication therapy against gastric Helicobacter pylori.

Background. The goal of this study was to see whether Helicobacter pylori (H. pylori) in the oral cavity might adversely affect the outcome of eradication therapy for gastric H. pylori. Materials and Methods. Forty-seven patients (36 males, 11 females) with gastric H. pylori infection were enrolled in this study. Gastric H. pylori infection was confirmed by both immunohistological staining with anti-H. pylori antibody and bacterial culture of biopsy specimens. The therapeutic regimen consisted of 30 mg/day lansoprazole, 750 mg/day metronidazole, and 400 mg/day clarithromycin administered for 2 weeks. A fragment of the H. pylori urease gene was amplified by nested PCR for DNA extracted from saliva and dental plaque from the same patients. We examined the correlation between the gastric eradication success rate and the prevalence of H. pylori in the oral cavity as determined by PCR before and after the eradication therapy. Results. The eradication success rate was significantly lower in the oral H. pylori-positive cases (12/23, 52.1%) than in the negative cases (22/24, 91.6%) at 4 weeks after the therapy (p = .0028). Two years later, only 16 of the 23 (69.5%) oral H. pylori-positive cases were disease-free, as compared to 23 of the 24 (95.8%) oral H. pylori-negative cases (p = .018). Conclusions.H. pylori in the oral cavity affected the outcome of eradication therapy and was associated with a recurrence of gastric infection. We recommend that oral H. pylori should be examined by nested PCR and, if positive, should be considered a causal factor in refractory or recurrent cases.