Molecular Detection of H. pylori Using Adherent Gastric Mucous to Biopsy Forceps.

BACKGROUND AND AIM: We assessed whether adherent gastric mucous to biopsy forceps instead of biopsy samples was suitable for the diagnosis of H. pylori infection. We confirmed the PCR methods to improve the diagnosis of H. pylori infection and clarithromycin (CAM) susceptibility.

METHODS: Gastric mucous was obtained by gently scraping gastric mucosa using biopsy forceps in patients undergoing upper gastrointestinal (GI) endoscopy for PCR and rapid urease test (RUT). DNA was extracted from gastric mucous present within the gel of RUT. H. pylori status and CAM susceptibility were evaluated using H. pylori-specific PCR amplification for 23S rRNA using 4 different primer sets and 16S rRNA. H. pylori positive was defined as two of the three tests (serum antibody, histology, and RUT or PCR) were positive. CAM susceptibility was evaluated by point mutations (A 2142G and A 2143G of 23S rRNA).

RESULTS: Samples taken from 494 subjects were evaluated: 300 H. pylori-positive patients and 194 negative patients. The results of PCR using DNA extracted from gastric mucous present within the RUT gel were consistent with those within water. The accuracy of 23S rRNA PCR for H. pylori detection using RUT samples was superior to the other tests. The frequency of CAM resistance was 38.9%, and eradication rate was 91.3% in the patients with wild-type and 47.0% in the patients with the mutant strains.

CONCLUSION: Adherent gastric mucous to biopsy forceps in RUT gel can be used for molecular testing to confirm the diagnosis of H. pylori infection and for CAM susceptibility.