Molecular testing methods have been developed and validated for fresh, frozen, or paraffin-embedded gastric mucosal biopsies; such testing has also been used effectively with fecal samples, which eliminates the need for endoscopy. Molecular methods such as polymerase chain reaction or fluorescently labeled nucleic acid hybridization can identify many of the mutations known to be responsible for antibiotic resistance.
Metronidazole resistance lowers eradication rates by approximately 25% in triple therapies; the impact of resistance is less in quadruple therapies and when PPIs are included in the regimen. Increasing the dose and duration of metronidazole improves outcomes in metronidazole-resistant strains, indicating that in vitro metronidazole resistance is not an absolute predictor of eradication failure, unlike clarithromycin and levofloxacin resistance.
Learn more about the treatment of H pylori.
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Cite this: B.S. Anand, Steven F. Moss. Fast Five Quiz: Helicobacter pylori - Medscape - Jan 20, 2022.