[Antibiotic-resistant H. pylori strains in the last ten years in Japan].

An increase in the prevalence of antibiotic-resistant H. pylori strains has been reported. We tested the sensitivity of H. pylori strains to antibiotics before and after the eradication treatment to determine primary and secondary resistance by E-test. A total of 336 H. pylori strains from 1987 to 1998 were tested for sensitivity to clarithromycin (CAM), amoxicillin (AMPC), and metronidazole (MNZ). Primary resistance of H. pylori to CAM, MNZ, and AMPC were found in 9.5%, 26.8%, and 0.3% strains, respectively. The resistant strains to CAM and MNZ were gradually increasing in the last few years. The cure rates of triple therapy with MNZ and CAM for CAM-susceptible and CAM-resistant H. pylori isolates were 83.3% (40/48) and 30.0% (3/10) respectively, and the cure rates of triple therapy with CAM and AMPC for CAM-susceptible and CAM-resistant H. pylori isolates were 79.3% (69/87) and 12.5% (1/8) respectively. After triple therapy, secondary resistant strains to CAM and MNZ were found in 42.1% (8/19) and 31.6% (6/19) of the cases.