Prevalence and virulence factors of Helicobacter pylori isolated from oral cavity of non-disease, gastritis, and gastric cancer patients.

BACKGROUND/PURPOSE: The oral cavity is considered a reservoir of Helicobacter pylori associated with gastric infection. It aimed to examine the prevalence of H. pylori strains from the oral cavity and gastric tissue of patients with different stage of gastric-diseases. Strains were further characterized for virulence genes, adhesion ability, and inflammation responses.

MATERIALS AND METHODS: 11 non-disease, 15 gastritis, and 15 gastric cancer participated in the study. After clinical examination, gastric biopsies, saliva and plaque samples were collected and H. pylori levels were examined by real-time PCR and cultivation. The cag A and vac A genes were investigated from the culture strains. Adhesion ability and pro-inflammatory responses were analyzed in comparison between the presence of virulent genes and disease status.

RESULTS: Relatively poor periodontal condition was found among gastric cancer patients. Prevalence of H. pylori- positive was 84.8% and 19.5% by real-time PCR and cultivation, respectively. The cag A and vac A gene-positive strains were 52.6% and 5.3%, respectively, which were found more in gastric cancer patients. The cag A gene-positive strains were found to be higher in gastric cancer patients, and strains had significantly higher adhesion ability and pro-inflammation expressions than the cag A gene-negative strains.

CONCLUSION: Colonization by H. pylori in oral cavity was confirmed, and the cag A gene-positive strains play a crucial role in both adhesion and inflammatory responses. The presence of H. pylori and its virulence gene in oral cavity should be received attention. An eradication of such strains from oral cavity may help to prevent the transmission and recolonization to gastric organs.