title: Resistance to metronidazole, clarithromycin and levofloxacin of Helicobacter pylori before and after clarithromycin-based therapy in Taiwan.
abstract: OBJECTIVE
  Clarithromycin-based triple therapy has been commonly applied as the first-line therapy for Helicobacter pylori eradication. Levofloxacin could serve as an alternative in either first-line or second-line regimens. This study surveyed the prevalence of levofloxacin resistance of H. pylori isolates in naive patients and in patients with a failed clarithromycin-based triple therapy.
  
  
  METHODS
  The study collected the H. pylori isolates from 180 naive patients and 47 patients with a failed clarithromycin-based triple therapy. Their in vitro antimicrobial resistance was determined by E-test.
  
  
  RESULTS
  The naive H. pylori isolates had resistance rates for amoxicillin, levofloxacin, clarithromycin and metronidazole of 0%, 9.4%, 10.6% and 26.7%, respectively. An evolutional increase of the primary levofloxacin resistance was observed in isolates collected after 2004, as compared to isolates collected before 2004 (16.3% vs 3.2%, P = 0.003). There was no evolutional increment of the primary clarithromycin resistance. The clarithromycin resistance elevated significantly after a failed clarithromycin-based triple therapy (78.7% vs 10.6%, P < 0.001). The post-treatment isolates remained to have a levofloxacin resistance rate of near 17%, but the levofloxacin-resistant isolates were correlated with a higher incidence of metronidazole resistance (P = 0.023). No strain was found to be resistant to amoxicillin even after eradication failure.
  
  
  CONCLUSIONS
  The levofloxacin resistance of naive H. pylori remains less than 10% in Taiwan. With relatively lower resistance to levofloxacin than to metronidazole of the H. pylori isolates collected after a failed clarithromycin-based therapy, proton pump inhibitor-levofloxacin-amoxicillin may be an alternative choice to serve as the second-line therapy.
authors.affiliation: Department of Internal Medicine, Medical College, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wei-Lun
authors.initials: WL
authors.lastname: Chang
authors.forename: Bor-Shyang
authors.initials: BS
authors.lastname: Sheu
authors.forename: Hsiu-Chi
authors.initials: HC
authors.lastname: Cheng
authors.forename: Yao-Jong
authors.initials: YJ
authors.lastname: Yang
authors.forename: Hsiao-Bai
authors.initials: HB
authors.lastname: Yang
authors.forename: Jiunn-Jong
authors.initials: JJ
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D044466:Asian People; D002648:Child; D017291:Clarithromycin / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000208:ethnology / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008795:Metronidazole / Q000627:therapeutic use*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015242:Ofloxacin / Q000627:therapeutic use*; D018579:Patient Selection; D015995:Prevalence; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D064704:Levofloxacin; D000658:Amoxicillin; D015242:Ofloxacin; D017291:Clarithromycin