Resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime.

The resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime was tested in 138 isolates, including 28 from treatment failures. No resistance to tetracycline was detected. Resistance to amoxicillin was found in one isolate (MIC = 1.5 mg/L) from an untreated patient, and resistance to cefixime in two isolates from each group (P = 0.18). Resistance to metronidazole and clarithromycin was much higher in the isolates from treated than from untreated patients: 60.7% and 38.2% for metronidazole (MIC >or= 8 mg/L) (P = 0.03); 46.4% and 8.2% for clarithromycin (MIC >or= 2 mg/L) (P < 0.001). Therapeutic outcome would benefit from susceptibility testing, especially after treatment failure.