Abstract
A three-site interlaboratory reproducibility evaluation of the Etest®concentration gradient strip method for testing antifungal susceptibilities was conducted using 30 strains of dermatophytes exposed to strips loaded with ketoconazole (KTZ), itraconazole (ITZ), amphotericin B (AMB) and fluconazole (FCZ). Etest®minimal inhibitory concentrations were compared with those obtained using a broth microdilution method. All isolates produced clearly detectable growth at 28 °C within 72–96 h for reading with the Etest®method. The highest interlaboratory agreement between Etest®and the microdilution method was shown with FCZ (94%), and the lowest was seen with KTZ (60%). Overall, agreement between the Etest®and microdilution method was variable. It was excellent for AMB (97%), good for ITZ (80%) and KTZ (77%), and low for fluconazole (27%).