title: The influence of metronidazole resistance on the efficacy of ranitidine bismuth citrate triple therapy regimens for Helicobacter pylori infection.
abstract: OBJECTIVE
  To assess the influence of metronidazole resistance on the efficacy of ranitidine bismuth citrate-based triple therapy regimens in two consecutive studies.
  
  
  METHODS
  In the first study, patients with a culture-proven Helicobacter pylori infection were treated with ranitidine bismuth citrate 400 mg, metronidazole 500 mg, and clarithromycin 500 mg, all twice daily for 1 week (RMC). In the second study, amoxycillin 1000 mg was substituted for clarithromycin (RMA). Susceptibility testing for metronidazole was performed with the E-test. Follow-up endoscopy was performed after >/= 4 weeks. Antral biopsy samples were taken for histology and urease test, and culture and corpus samples for histology and culture.
  
  
  RESULTS
  112 patients, 53 males, age 55 +/- 14 years (39 duodenal ulcer, 7 gastric ulcer and 66 gastritis) were treated with RMC, and 89 patients, 52 males, age 58 +/- 15 years (23 duodenal ulcer, 7 gastric ulcer and 59 gastritis) were treated with RMA. For RMC, intention-to-treat eradication results were 98% (59/60, 95% CI: 91-100%) and 95% (20/21, 95% CI: 76-100%) for metronidazole susceptible and resistant strains, respectively (P = 0.45). For RMA these figures were 87% (53/61, 95% CI: 76-94%) for metronidazole susceptible strains and 22% (2/9, 95% CI: 3-60%) for resistant strains (P = 0.0001).
  
  
  CONCLUSIONS
  Both regimens are effective in metronidazole susceptible strains. However, in contrast to the amoxycillin-containing regimen, that containing clarithromycin is also effective in resistant strains.
authors: Department of Internal Medicine, Bethesda Hospital, Hoogeveen, the Netherlands.
authors: E J
authors: EJ
authors: Van der Wouden
authors: J C
authors: JC
authors: Thijs
authors: A A
authors: AA
authors: Zwet
authors: A
authors: A
authors: Kooy
authors: J H
authors: JH
authors: Kleibeuker
mesh_terms: D000328:Adult; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D001729:Bismuth / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination; D004381:Duodenal Ulcer / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D005756:Gastritis / Q000188:drug therapy / Q000382:microbiology; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology*; D010406:Penicillins / Q000627:therapeutic use; D011899:Ranitidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013276:Stomach Ulcer / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D010406:Penicillins; D008795:Metronidazole; C073340:ranitidine bismuth citrate; D000658:Amoxicillin; D011899:Ranitidine; D017291:Clarithromycin; D001729:Bismuth