Efficacy of metronidazole for the treatment of clarithromycin-resistant Helicobacter pylori infection in a Japanese population

Background. Eradication of Helicobacter pylori has become a common treatment for several diseases. There is an increase in antibiotic-resistant strains, which causes the failure of eradication. The aim of this study was to investigate the usefulness of metronidazole for the treatment of H. pylori infection in patients who failed eradication therapy. Methods. Seventy H. pylori-positive patients who had failed eradication treatment with first-line triple therapy, which consisted of a proton pump inhibitor, amoxicillin, and clarithromycin, were enrolled into the study. Before the second-line therapy, patients underwent endoscopy to obtain H. pylori strains to test susceptibility to antibiotics. Lansoprazole (30 mg b.d.), amoxicillin (750 mg b.d.), and metronidazole (250 mg b.d.) were administered for 1 week, and the result was tested by C-13-UBT. Results. H. pylori was isolated from 62 patients, and 52 of them (83.9%) were clarithromycin resistant. There was no amoxicillin- or metronidazole-resistant strain. No major adverse effects were seen, and all the patients completed the 1-week regimen. The eradication rates of lansoprazole-amoxicillin-metronidazole were 96.2% (51/53; 95% CI, 87.0%-99.5%) using both intention-to-treat analysis and per protocol analysis. Conclusions. Lansoprazole-amoxicillin-metronidazole triple therapy is an effective and promising second-line H. pylori eradication therapy in a north Japanese population, which has a low frequency of metronidazole resistance.