title: Change in antibiotic resistance of Helicobacter pylori strains and the effect of A2143G point mutation of 23S rRNA on the eradication of H. pylori in a single center of Korea.
abstract: BACKGROUND
  The current prevalence of primary antibiotic resistance of H. pylori is not known in Korea. This study was done to evaluate the prevalence of primary antibiotic resistance of H. pylori, and to evaluate the effect of point mutations of 23S rRNA on the rate of eradication of H. pylori.
  
  
  METHODS
  H. pylori were isolated from gastric mucosal biopsy specimens obtained from 222 Koreans. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, and levofloxacin were examined using the agar dilution method. DNA sequencing was carried out to detect H. pylori 23S rRNA mutations.
  
  
  RESULTS
  The resistance to clarithromycin, tetracycline, ciprofloxacin, and levofloxacin increased during the period of 2007 to 2009 compared with 2003 to 2005 (P<0.05). However, amoxicillin and metronidazole resistance slightly decreased. The rates of eradication were 95.5% for the clarithromycin-sensitive strains, which was higher than the 67.9% for the clarithromycin-resistant strains (P=0.001). By contrast, the eradication rate was 100% in patients with amoxicillin-resistant H. pylori. Among 26 clarithromyin-resistant strains, 6 (23%) had A2143G mutations, and all of the cases in which these mutations were present were not eradicated by proton pump inhibitor-based triple therapy (P=0.0004). By contrast, none of the 26 clarithromyin-sensitive strains had A2143G mutations. The T2183C and A2223G mutations were frequently found in the sensitive strains and in the resistant strains.
  
  
  CONCLUSIONS
  Clarithromycin resistance of H. pylori, which determined the efficacy of H. pylori eradication of proton pump inhibitor triple regimen, was found to be increased in a single center study. A2143G was an important 23S rRNA mutation associated with clarithromycin resistance and affected the H. pylori eradication efficacy.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoungnam, Gyeonggi-do, Korea.
authors.forename: Tae Jun
authors.initials: TJ
authors.lastname: Hwang
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Hong Bin
authors.initials: HB
authors.lastname: Kim
authors.forename: Byoung Hwan
authors.initials: BH
authors.lastname: Lee
authors.forename: Ryoung Hee
authors.initials: RH
authors.lastname: Nam
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Mi Kyoung
authors.initials: MK
authors.lastname: Lee
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
authors.forename: Hyun Chae
authors.initials: HC
authors.lastname: Jung
authors.forename: In Sung
authors.initials: IS
authors.lastname: Song
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001706:Biopsy; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017354:Point Mutation; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D012338:RNA, Ribosomal, 23S; D056910:Republic of Korea; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D054328:Proton Pump Inhibitors; D012338:RNA, Ribosomal, 23S