Oral colonization is unlikely to play an important role in Helicobacter pylori infection

Background This clinical and microbiological study investigated whether Helicobacter pylori colonizes the mouth en route to the pyloric antrum. It has been suggested that oral colonies are a source of reinfection after eradication of gastric infection. Methods Some 208 patients attending for routine diagnostic endoscopy for dyspepsia were recruited. Before endoscopy, samples were collected of saliva, supragingival and infragingival plaque, and swabs were taken from the tongue, mouth and pharynx. At endoscopy, gastric antral biopsies were taken for the rapid urease test, culture and histological examination. Gastric and duodenal juice samples were aspirated. Restriction nuclease digestion with HaeIII was employed on all specimens from patients in whom there was evidence of the organism in the mouth. Results H. pylori was observed in dental plaque in only 15 patients, all from the 116 who had evidence of the organism in the stomach. Restriction endonuclease digestion demonstrated that in 13 of the 15 patients the strains were identical in mouth and stomach. Conclusion Oral colonization is a rare event, but does occur. Its rarity suggests that it is not an important factor in reinfection.