, Volume 40, Issue 2, pp 96-100

Clarithromycin and Amoxicillin Susceptibility of Helicobacter pylori Strains Isolated from Adult Patients with Gastric or Duodenal Ulcer in Italy

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Helicobacter pylori strains, isolated from 100 gastric biopsies from 49 previously untreated adult patients with endoscopy and histology-confirmed gastric or duodenal ulcer, were tested for in vitro antimicrobial susceptibility. Strains were isolated from biopsies of 75.5% (37 of 49) patients before therapy and of 13.5% after therapy. Clarithromycin and amoxicillin susceptibility testing was performed on pretreatment and posttreatment strains by using the agar disk diffusion method and E-test, a quantitative technique for the minimal inhibitory concentration (MIC) determination. All strains (n = 53) were susceptible to amoxicillin by the two methods. Three strains of 34 (8.8%) patients were resistant to clarithromycin: two by both methods and one by E-test (MIC > 2 μg/ml). E-test, although more expensive than the disk diffusion method, is easy to perform and is a reliable method for testing H. pylori susceptibility to antimicrobial agents in the clinical microbiology laboratory.

Received: 24 June 1999 / Accepted: 25 August 1999