title: Antibiotic resistance of Helicobacter pylori strains in Japanese children.
abstract: The resistance of Helicobacter pylori to the recently available antibiotic treatment regimens has been a growing problem. We investigated the prevalence of H. pylori resistance to clarithromycin, metronidazole, and amoxicillin among 51 H. pylori isolates from Japanese children. In addition, the mutations of the corresponding gene were studied by PCR and restriction fragment length polymorphism analysis. Primary resistance to clarithromycin, metronidazole, and amoxicillin was detected in 29, 24, and 0% of strains, respectively. The eradication rates in clarithromycin-susceptible and -resistant strains were 89 and 56%, respectively (P < 0.05). The prevalence of strains with acquired resistance to clarithromycin (78%) was higher than that of strains with primary resistance (P < 0.01). Among the clarithromycin-resistant strains studied, 92% showed cross-resistance to azithromycin. No acquired resistance to amoxicillin was demonstrated. The A2144G mutation in the 23S rRNA gene was detected in 11 of 12 (92%) clarithromycin-resistant strains tested, whereas the mutation was not detected in any of the 15 susceptible strains. The deletion of the rdxA gene was not demonstrated in any of the strains. The results indicate that a high prevalence of clarithromycin-resistant strains is associated with eradication failure. Testing of susceptibility to clarithromycin is recommended.
authors.affiliation: Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan. skato@ped.med.tohoku.ac.jp
authors.forename: Seiichi
authors.initials: S
authors.lastname: Kato
authors.forename: Shigeru
authors.initials: S
authors.lastname: Fujimura
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Udagawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Shimizu
authors.forename: Shunichi
authors.initials: S
authors.lastname: Maisawa
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ozawa
authors.forename: Kazuie
authors.initials: K
authors.lastname: Iinuma
mesh_terms: D000293:Adolescent; D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007564:Japan; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009601:Nitroreductases / Q000235:genetics; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012338:RNA, Ribosomal, 23S / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D012338:RNA, Ribosomal, 23S; D008795:Metronidazole; D000658:Amoxicillin; C029492:aromatic NADH-dependent nitroreductase; D009601:Nitroreductases; D017291:Clarithromycin