title: Is antimicrobial susceptibility testing necessary before second-line treatment for Helicobacter pylori infection?
abstract: BACKGROUND
  An antimicrobial susceptibility test for Helicobacter pylori before second-line treatment is often performed, although whether the test is truly necessary remains unknown.
  
  
  METHODS
  Eighty-two patients with H. pylori infection for whom first-line treatment with a 1-week proton pump inhibitor/amoxicillin-clarithromycin (AC) regimen had failed were randomly assigned to two groups: those having or not having the susceptibility test before re-treatment. The cure rates for these two groups were compared.
  
  
  RESULTS
  Five of the 82 patients were excluded from the analysis. For 38 patients in the susceptibility-test group, we used what we considered the best regimen based on susceptibility testing: 10 patients [no resistance to clarithromycin (CAM)] received the lansoprazole-amoxicillin-clarithromycin regimen, 22 patients [19 CAM resistant, metronidazole (MNZ) susceptible; three failure of culture] were given the lansoprazole-amoxicillin-metronidazole (LAM) regimen, and six patients (both MNZ and CAM resistant) received dual therapy with omeprazole (OPZ) and amoxicillin (AMOX) in which the OPZ dose was determined by the CYP2C19 gene polymorphism. For 39 patients in the group with no susceptibility testing, LAM regimens were prescribed. The intention-to-treat (ITT)-based cure rates in the groups with and without susceptibility testing were 81.6% (95% confidence interval; 66-92%) and 92.4% (79-98%), respectively, and there was no significant difference between these two groups.
  
  
  CONCLUSIONS
  Susceptibility testing is not necessarily required before second-line therapy if the first-line treatment has been performed using proton pump inhibitor/AC regimens.
authors.affiliation: Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Miwa
authors.forename: A
authors.initials: A
authors.lastname: Nagahara
authors.forename: A
authors.initials: A
authors.lastname: Kurosawa
authors.forename: T
authors.initials: T
authors.lastname: Ohkusa
authors.forename: R
authors.initials: R
authors.lastname: Ohkura
authors.forename: M
authors.initials: M
authors.lastname: Hojo
authors.forename: N
authors.initials: N
authors.lastname: Enomoto
authors.forename: N
authors.initials: N
authors.lastname: Sato
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents; D001944:Breath Tests; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents