title: The effect of antibiotic resistance on the outcome of three 1-week triple therapies against Helicobacter pylori.
abstract: BACKGROUND
  Resistance of Helicobacter pylori to antibiotics may be a major reason for treatment failure.
  
  
  OBJECTIVE
  To evaluate the effect of primary H. pylori resistance to antibiotics on the cure rates of three anti-H. pylori 1-week triple therapies.
  
  
  METHODS
  One hundred and sixteen consecutive patients diagnosed H. pylori-positive by gastric histology, rapid urease test and culture were enrolled. Activity of tested antibiotics was determined by means of the E-test. Patients were treated for 7 days with: (i) pantoprazole 40 mg o.d. plus amoxycillin 1 g b.d. and metronidazole 250 mg q.d.s. (PAM); (ii) pantoprazole 40 mg o.d. plus clarithromycin 250 mg b.d. and metronidazole 250 mg q.d.s. (PCM); or (iii) pantoprazole 40 mg o.d. plus amoxycillin 1 g b.d. and clarithromycin 250 mg b.d. (PAC). Two months after completion of therapy, endoscopy and gastric biopsies were repeated.
  
  
  RESULTS
  Primary resistance rates to metronidazole, clarithromycin and amoxycillin were 17.2, 6.9 and 0%, respectively. Overall H. pylori cure rates expressed as intention-to-treat and per protocol analyses were, respectively, 79% and 86% with PAM, 82% and 89% with PCM, and 85% and 85% with PAC. Significantly lower cure rates were observed in metronidazole-resistant patients treated with PAM (56% vs. 96%, P = 0.01) or PCM (50% vs. 97%, P = 0.01). A trend towards lower H. pylori cure rates was observed in clarithromycin-resistant patients treated with PCM (67% vs. 91%, P = 0.74) or PAC (50% vs. 87%, P = 0.68).
  
  
  CONCLUSIONS
  Primary resistance to metronidazole influences the H. pylori cure rate of anti-H. pylori proton pump inhibitor-based triple therapies which include this antibiotic. A similar trend exists for primary clarithromycin resistance.
authors.affiliation: Department of Geriatrics, S. Bortolo Hospital, Vicenza, Italy. pilotto@mbox.avnet.it
authors.forename: A
authors.initials: A
authors.lastname: Pilotto
authors.forename: G
authors.initials: G
authors.lastname: Leandro
authors.forename: M
authors.initials: M
authors.lastname: Franceschi
authors.forename: M
authors.initials: M
authors.lastname: Rassu
authors.forename: L
authors.initials: L
authors.lastname: Bozzola
authors.forename: F
authors.initials: F
authors.lastname: Furlan
authors.forename: F
authors.initials: F
authors.lastname: Di Mario
authors.forename: G
authors.initials: G
authors.lastname: Valerio
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000008:administration & dosage / Q000009:adverse effects; D001562:Benzimidazoles / Q000008:administration & dosage / Q000009:adverse effects; D017291:Clarithromycin / Q000008:administration & dosage / Q000009:adverse effects; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination; D005260:Female; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000008:administration & dosage / Q000009:adverse effects; D008875:Middle Aged; D009853:Omeprazole / Q000031:analogs & derivatives; D000077402:Pantoprazole; D011446:Prospective Studies; D013454:Sulfoxides / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D001562:Benzimidazoles; D013454:Sulfoxides; D008795:Metronidazole; D000658:Amoxicillin; D000077402:Pantoprazole; D017291:Clarithromycin; D009853:Omeprazole