title: Effect of ornidazole and clarithromycin resistance on eradication of Helicobacter pylori in peptic ulcer disease.
abstract: BACKGROUND
  Clarithromycin and nitroimidazoles such as metronidazole and ornidazole are among the most frequently used antibiotics for curing Helicobacter pylori infection. However, controversial data exist on whether their in vitro resistance has a negative impact on treatment outcome.
  
  
  METHODS
  Patients with H. pylori positive active peptic ulcer disease were randomly assigned to receive lansoprazole 30 mg o.d., amoxycillin 1 g b.d. and ornidazole 500 mg b.d. (LAO) or lansoprazole 30 mg o.d., amoxycillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC) for 2 weeks. Pre-treatment resistance to ornidazole and clarithromycin was assessed by Epsilometer (E-) test. Four weeks after completion of treatment, patients underwent a 13C urea breath test to assess H. pylori status.
  
  
  RESULTS
  Data from 80 patients with active peptic ulcer disease and positive H. pylori status were analysed. The prevalence of primary drug resistance was 25% for metronidazole and 7.5% for clarithromycin. In patients treated with LAO, effective treatment was achieved in 87% of metronidazole-susceptible, but only 30% of metronidazole-resistant strains (P < 0.01). In the LAC group, therapy was successful in 81% of clarithromycin-susceptible strains, whereas treatment failed in all patients with primary clarithromycin resistance (n = 3).
  
  
  CONCLUSIONS
  Resistance against nitroimidazoles significantly affects treatment outcome in H. pylori eradication therapy.
authors.affiliation: Division of Gastroenterology, University Hospital of Basel, Switzerland.
authors.forename: F S
authors.initials: FS
authors.lastname: Lehmann
authors.forename: J
authors.initials: J
authors.lastname: Drewe
authors.forename: L
authors.initials: L
authors.lastname: Terracciano
authors.forename: C
authors.initials: C
authors.lastname: Beglinger
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000293:Adolescent; D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000897:Anti-Ulcer Agents / Q000627:therapeutic use; D017291:Clarithromycin / Q000627:therapeutic use*; D004338:Drug Combinations; D004352:Drug Resistance, Microbial; D016099:Endoscopy, Gastrointestinal; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori; D006801:Humans; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000031:analogs & derivatives / Q000627:therapeutic use; D009950:Ornidazole / Q000627:therapeutic use*; D010406:Penicillins / Q000627:therapeutic use; D010437:Peptic Ulcer / Q000188:drug therapy* / Q000382:microbiology; D016896:Treatment Outcome
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D004338:Drug Combinations; D010406:Penicillins; D064747:Lansoprazole; D009950:Ornidazole; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole