OBJECTIVETo analyze the relationship between Helicobacter pylori (Hp) in oral cavity and the Hp infection in stomach.

METHODS102 patients with gastric Hp infection and periodontitis were enrolled in this study. DNA was extracted from subgingival plaques, mouthwashes and stomach mucosa samples by using the glass-milk (SiO2) purification method. To identify the presence of Hp in these samples, PCR (polymerase chain reaction) was carried out, and two pairs of oligonucleotide primer were used to amplify a portion of gene urease C and gene cag A of Hp.

RESULTSThe rate of Hp detected in oral cavity was significantly higher in patients with positive Hp in stomach (43.1%, n=58) than in those with negative Hp in stomach (22.7%, n=44, P<0.05). After the treatment for gastric Hp infection for 4 weeks, the eradication rate of Hp in stomach was lower, but only slightly in patients with positive oral Hp (16/25, 64%) than in those with negative oral Hp (24/33, 72.7%). However, this difference became apparent (36.0% vs 63.6%, P<0.05) after one year of the treatment.

CONCLUSIONSThe effectiveness of the eradication therapy for gastric Hp infection is affected by the presence of Hp in oral cavity. Oral colonization of Hp may imply that there is a risk of the relapses of gastric and duodenal Hp infection and ulcer after the antibiotics treatment for the eradication of Hp.