Prevalence and clinical significance of antibiotic resistance in Helicobacter pylori

AIMS: to determine the rates of resistance of H. pylori to antibiotics and proton pump inhibitors (PPI) in an area of southern Spain, and the evolutio n of resistance during the last 3 years. To study the relationship between the resistance profile of H. pylori and age, sex, smoking habit, previous t reatment with PPI and successful eradication. METHODS: one hundred and thirty-nine patients with positive H. pylori cultu re were enrolled in the study. In 91 patients, sensitivity studies were don e for erythromycin, clarithromycin, metronidazole, tetracycline and amoxici llin using E-tests, and for omeprazole using the agar dilution test. Treatm ent with omeprazole, clarithromycin and amoxicillin was started and the ure a breath test was used to confirm successful eradication. RESULTS: thirty-five patients (38.5%) showed some antibiotic resistance: 26 cases (29%) against metronidazole, 9 (10%) against clarithromycin, and 11 (13%) against erythromycin. No patients showed resistance against amoxicill in, omeprazole or tetracycline. Previous omeprazole treatment was related w ith a higher rate of metronidazole resistance (57% vs 31%; p < 0.05), as wa s age (41% in patients youn- ger than 40 years vs 11% in patients older tha n 60 years; p < 0.005). There was no correlation between smoking or sex and resistance. Clarithromycin resistance was related to unsuccessful eradicat ion (33% vs 75%; p < 0.05). Metronidazole resistance did not influence the effectiveness of clarithromycin-based triple therapy. Clarithromycin resist ance changed little during the 3-year study period, but the rate of metroni dazole resistance rose, although the change was not significant (23% in 199 6 vs 34% in 1998; p = NS). CONCLUSIONS: resistance to metronidazole and clarithromycin were similar to the rates in other areas of Spain. Younger patients with previous omeprazo le treatment were more frequently resistant to metronidazole, but not to om eprazole. Clarithromycin resistance was related to unsuccessful eradication with clarithromycin-based triple therapy. During the 3-year study period t here were no changes in resistance rates.