RESUMEN
OBJECTIVE: Resistance to antibiotics is the major cause of treatment failure of Helicobacter pylori (HP) infection. The culture-guided triple therapy (chosen on the basis of a preliminary in-vitro susceptibility test) might help to increase treatment success in high antibiotic resistance regions. The aim of this study was to evaluate the effectiveness of treatment with clarithromycin in patients with clarithromycin-sensitive culture compared with patients treated empirically. METHODS: In this prospective and controlled trial, 111 naive HP-positive patients were randomized to receive standard triple therapy omeprazole (20 mg twice daily), amoxicillin (1 g twice daily), and clarithromycin (500 mg twice daily) for 10 days (OAC) after antimicrobial susceptibility testing if there was no resistance to clarithromycin (ClariS) or empirical 10-day OAC for first-line therapy of HP (ClariNA). Eradication was confirmed using the C-labelled urea breath test 6 weeks after therapy. Our primary outcome was HP eradication. Treatment adherence and adverse effects were recorded. RESULTS: The effectiveness of eradication by protocol with 10-day OAC therapy in the ClariS was 94% [95% confidence interval (CI): 0.83-0.98], which was 22% higher than ClariNA 72% (95% CI: 0.58-0.85; P=0.006). The odds ratio of eradication in ClariS was 1.30 (95% CI: 1.10-1.60; P<0.05 by logistic regression) and the number needed to treat was 5 (95% CI: 3-13). We found no significant difference in the occurrence of adverse effects or in compliance between the two groups. CONCLUSION: The eradication rate was significantly higher with clarithromycin-based triple therapy for patients with clarithromycin-susceptible HP isolates compared with those for whom no information on the corresponding susceptibility was available (ClinicalTrials.gov number NCT01486082).