title: Prevalence of primary and secondary antimicrobial resistance of Helicobacter pylori in Korea from 2003 through 2012.
abstract: BACKGROUND
  Antimicrobial resistance of Helicobacter pylori (H. pylori) affects the efficacy of eradication therapy. The aim of this study was to estimate the prevalence of primary and secondary resistance of H. pylori isolates to antibiotics and to characterize the risk factors associated with antimicrobial resistance in Korea.
  
  
  METHODS
  This study was performed during the period of 2003-2012. Primary resistance was evaluated from 347 patients without any history of eradication, and secondary resistance was evaluated in 86 patients from whom H. pylori was cultured after failure of eradication. Minimal inhibitory concentration test was performed for amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, levofloxacin, and moxifloxacin using agar dilution method. Primary and secondary resistance rates of H. pylori to 7 antibiotics were evaluated and risk factors for the antibiotic resistance were analyzed.
  
  
  RESULTS
  Increase in the primary resistance rate was found in amoxicillin (6.3-14.9%, p = .051), clarithromycin (17.2-23.7%, p = .323), and both of levofloxacin and moxifloxacin (4.7-28.1%, p = .002) during the study period. Secondary resistance rate significantly increased in metronidazole, levofloxacin, and moxifloxacin. Increase of resistance occurred after initial failure of eradication therapy in case of clarithromycin (p < .001), azithromycin (p < .001), levofloxacin (p = .011), and moxifloxacin (p = .020). Multivariable analyses showed that clarithromycin, azithromycin, levofloxacin, and moxifloxacin resistance was associated with previous eradication treatment history.
  
  
  CONCLUSIONS
  The increased primary and secondary antibiotic resistance of H. pylori in Korea is ongoing, and it will become a significant limitation for effective eradication of H. pylori in the future.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Jung Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Jung Mogg
authors.initials: JM
authors.lastname: Kim
authors.forename: Ryoung Hee
authors.initials: RH
authors.lastname: Nam
authors.forename: Hyun
authors.initials: H
authors.lastname: Chang
authors.forename: Jae Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Shin
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
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents