EXPLANATIONS FOR HIGH-RATES OF ERADICATION WITH TRIPLE THERAPY USING METRONIDAZOLE IN PATIENTS HARBORING METRONIDAZOLE-RESISTANT HELICOBACTER-PYLORI STRAINS

In 4 of 17 Helicobacter pylori strains obtained from antral biopsy sam ples, the registered primary resistance (MIC, >32 mu g/ml) appeared to be nonstable after prolonged microaerophilic incubation. In all resis tant strains tested, susceptibility could be obtained when culture und er normal microaerophilic conditions was preceded by a period of anaer obic incubation. Both of these findings may explain the observed discr epancy between the results of in vitro susceptibility tests and the er adication obtained in vivo.