METRONIDAZOLE RESISTANCE - A PREDICTOR OF FAILURE OF HELICOBACTER-PYLORI ERADICATION BY TRIPLE THERAPY

Triple therapy (bismuth and two antibiotics) will eradicate Helicobact er pylori infection in 70-90% of subjects. Treatment failure has been attributed to patient compliance and antimicrobial drug resistance. Th e aim of this study was to examine factors influencing the eradication of H. pylori following triple therapy. Thirty seven subjects with N. pylori cultured from antral biopsies were treated with colloidal bismu th subcitrate (120 mg qid for 2 weeks), metronidazole (400 mg rid for 1 week) and amoxycillin (500 mg rid for 1 week). Pretreatment isolates of H. pylori were tested for metronidazole susceptibility by agar dil ution according to the National Committee for Clinical Laboratory Stan dards guidelines. Factors including age, sex, clinical diagnosis and m etronidazole resistance were evaluated in relation to H. pylori. The o verall metronidazole resistance was 32%. Metronidazole resistant strai ns were more frequent in females, with a resistance rate of 54%. Helic obacter pylori eradication occurred in 68% of patients with a metronid azole susceptible stain and only 17% of patients with a metronidazole resistant strain (P < 0.03). Helicobacter pylori eradication is depend ent upon susceptibility to metronidazole. This data would support. the role for routine metronidazole susceptibility resting using appropria te standardized methods when triple therapy is to be considered.