title: Comparative evaluation of the E test, agar dilution, and broth microdilution for testing susceptibilities of Helicobacter pylori strains to 20 antimicrobial agents.
abstract: The Epsilometer test (E test; AB Biodisk, Solna, Sweden), a new quantitative technique for the determination of antimicrobial susceptibility, was compared to reference methods (agar dilution and broth microdilution) for the antimicrobial susceptibility testing of Helicobacter pylori. Seventy-one H. pylori strains isolated from patients with duodenal ulcers were tested against 20 antimicrobial agents. The E test and the agar dilution method were carried out on Mueller-Hinton agar; the broth microdilution method was performed with Mueller-Hinton broth. The E-test results showed excellent correlation with the agar dilution results, with 91.3 and 98.8% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,350 tests. The correlation between the E-test results and the broth microdilution results was slightly higher, with 91.6 and 99.1% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,317 tests. There were six major errors and two very major errors by the metronidazole E test compared to the results obtained by reference methods. Excellent agreement between E-test, agar dilution, and broth microdilution results was found for resistance to erythromycin (8%), clarithromycin (6%), and tetracycline (6%). Our results confirm that the E test is comparable to standardized methods for susceptibility testing. Therefore, the E test is a reliable and alternative method for testing H. pylori susceptibility to a wide range of antimicrobial agents in clinical practice.
authors.affiliation: Department of Biomedical Sciences, G. D'Annunzio University, Chieti, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Piccolomini
authors.forename: G
authors.initials: G
authors.lastname: Di Bonaventura
authors.forename: G
authors.initials: G
authors.lastname: Catamo
authors.forename: F
authors.initials: F
authors.lastname: Carbone
authors.forename: M
authors.initials: M
authors.lastname: Neri
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016480:Helicobacter pylori / Q000187:drug effects*; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents