Background: Helicobacter pylori has been associated with the development of peptic ulcers and gastric cancer. Although it may be transmitted through the oral cavity, it is unknown whether the oral cavity acts as a permanent reservoir for this bacterium. The purpose of this study was to use nested polymerase chain reaction (PCR) to clarify whether the oral cavity acts as a reservoir for H. pylori.
Methods: The existence of H. pylori in the oral cavity was determined by nested PCR in 57 subjects and by culture method in 18 subjects. The presence of periodontopathic bacteria was also determined by 16S rRNA-based PCR method.
Results: Although H. pylori was rarely detected in the oral cavity by culture technique, it was frequently detected (35.1%) by nested PCR in the oral cavity, especially among periodontitis patients who had the bacterium in the gastrointestinal tract (46.4%). Among the subjects who harbored H. pylori in the stomach or duodenum, 41.2% of patients with periodontal pockets > or = 4 mm and 9.1% of subjects without pockets showed H. pylori in dental plaque, although a statistically significant difference was not observed. One patient who had periodontal pockets retained H. pylori in the oral cavity even after eradication of the bacterium from the stomach and duodenum. Most (8/10) of the patients who had H. pylori in dental plaque harbored Bacteroides forsythus in their oral cavities.
Conclusion: Close attention should be given to periodontitis patients who harbor H. pylori in the oral cavity.