Randomized trial of omeprazole and clarithromycin combined with either metronidazole or amoxycillin in patients with metronidazole-resistant or -susceptible Helicobacter pylori strains

Background: The impact of metronidazole resistance on the efficacy of proto n pump inhibitor based triple therapies remains unclear. Aim: To study whether metronidazole resistance affects Helicobacter pylori eradication rates in patients treated for 1 week. with either omeprazole 20 mg b.d., metronidazole 400 mg b.d. and clarithromycin 350 mg b.d. (OMC), o r omeprazole 20 mg b.d., amoxycillin 1000 mg b.d. and clarithromycin 500 mg b.d. (OAC). Methods: A randomized, single blind, single centre study with parallel grou ps was conducted. H. pylori positive patients were enrolled in a metronidaz ole-resistant (MR: MIC > 8 mu g/mL) or a metronidazole-susceptible group (M S; MIC < 4 mu g/mL), as determined by E-test, Within the strata patients we re randomized to either OAC or OMC. Results: One hundred and twenty-two patients were included. The per protoco l cure rate for OAC was 52 out of 57 (91%) (MS 23 out of 26 (89%); MR 29 ou t of 31 (94%)) and for OMC 46 out of 55 (84%) (MS 19 out of 22 (86%): MR 27 out of 33 (82%)). Conclusions: One-week OAC and OMC are effective therapies, OAC and OMC were equally effective in patients with metronidazole-susceptible strains of H. pylori. Using the OMC regimen, neither equality nor significant difference s in treatment outcome could be shown between patients with metronidazole-r esistant or -susceptible strains of H. pylori.