Abstract
To investigate amoxicillin and metronidazole resistance of Helicobacter pylori, we compared putative resistance genes between resistant strains obtained in vitro and their sensitive parent strain. All metronidazole-resistant strains had rdxA mutations, and an amoxicillin-resistant strain had pbp1 and pbp2 mutations. By transforming PCR products of these mutated genes into antibiotic-sensitive strains, we showed that rdxA null mutations were sufficient for metronidazole resistance, while pbp1 mutations contributed to amoxicillin resistance of H. pylori.