Update on clarithromycin resistance in Helicobacterpylori in Hong Kong and its effect on clarithromycin-based triple therapy

Abstract

Aim To update the antibiotic susceptibility of Helicobacter pylori andevaluate the efficacy of a clarithromycin-based triple therapy in rela-tion to metronidazole and/or clarithromycin resistance in Hong Kong. Methods Consecutive patients referred for upper endoscopy due todyspeptic symptoms were recruited. Gastric biopsies were obtainedfor the CLO test, histology and culture. Antibiotic susceptibility wasassessed by the E-test. Patients with H. pylori infection receivedrabeprazole 20mg, clarithromycin 500 mg, and amoxicillin 1000mg,all twice daily for 7 days.13C-urea breath test was performed threemonths after treatment.Results A total of 125 patients were recruited. Culture of H. pyloriwas successful in 102 (81.6%) patients. The prevalence of antibioticresistance to metronidazole, clarithromycin and amoxicillin were39.2%, 4.9% and 0%, respectively. A total of 86 patients received oneweek triple therapy, and 81 patients attended the follow-up test. Erad-ication rates by per protocol and intention-to-treat analysis were92.6% and 87.2%, respectively. The regimen achieved significantlyhigher eradication rate for patients with clarithromycin sensitivestrains than that for those with clarithromycin resistant strains (94.8%vs. 50%, P = 0.027), whereas there was no significant difference inthe eradication rate between metronidazole-sensitive and resistantstrains.Conclusion The updated prevalence of resistance to metronida-zole, clarithromycin and amoxicillin in Hong Kong is 39.2%, 4.9%and 0%, respectively. Clarithromycin resistance influences the clini-cal efficacy of clarithromycin-based triple therapy. However due tothe low prevalence of clarithromycin resistance, clarithromycin-basedtherapy is still the first choice for clinical use.(This study is supported by a research grant from the Hong KongDigestive Foundation, Hong Kong.)