Influence of metronidazole resistance on efficacy of quadruple therapy for Helicobacter pylori eradication

R W M van der Hulst,^a A van der Ende,^b A Homan,^a P Roorda,^b J Dankert,^b G N J Tytgat^a

^a Department of Gastroenterology, ^b Department of Medical Microbiology, Academic Medical Centre, Amsterdam, The Netherlands

Correspondence to: Dr R W M van der Hulst, Department of Gastroenterology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.

Accepted for publication 10 July 1997

BackgroundMetronidazole-containing eradication therapies are less effective for metronidazole resistant Helicobacter pylori. Although early data suggested improvement of the efficacy of bismuth triple therapy after the addition of acid suppressives, these findings were based on studies with small numbers of patients, incomplete post-eradication follow up, or omission of pretreatment susceptibility testing.
AimsTo study the efficacy of quadruple therapy in the Amsterdam area, where the efficacy of bismuth triple therapy has been proved to be affected by metronidazole resistance.
Patients and methodsEighty two consecutive dyspeptic H pylori positive patients with either metronidazole susceptible (group I) or metronidazole resistant H pylori strains (group II) received quadruple therapy for one week: omeprazole 20 mg twice daily; colloidal bismuth subcitrate 120 mg four times a day; tetracycline 500 mg four times a day; metronidazole 500 mg three times a day. Susceptibility to metronidazole was determined by the E-test.
ResultsIntention to treat analysis showed that H pylori infection had been cured in 42/43 patients (98%) in group I and 32/39 patients (82%) in group II (p = 0.02).
ConclusionThe efficacy of quadruple therapy is significantly impaired in patients infected with metronidazole resistant H pylori. Therefore a non-metronidazole-containing regimen should preferably be used in areas known to have a high prevalence of pretreatment metronidazole resistance.
(GUT 1998;42:166-169)

Keywords: quadruple therapy;  metronidazole resistance;  Helicobacter pylori;  gastritis;  duodenal ulcer disease