Comparison of Etest, microdilution and colorimetric dilution with reference broth macrodilution method for antifungal susceptibility testing of clinically significant Candida species isolated from immunocompromised patients

Abstract

Amphotericin B and fluconazole macrodilution minimum inhibitory concentration values of 101 Candida strains isolated from 91 immunocompromised patients were comparatively evaluated with the results of Etest, microdilution and colorimetric microdilution methods. The overall agreement rates of Etest, microdilution and colorimetric microdilution methods with the reference macrodilution method were found to be acceptably high after an incubation period of 24 and 48 h (varying from 86 to 93% for amphotericin B and from 84 to 89% for fluconazole). In addition, the results pointed out relatively high minimum inhibitory concentration values of fluconazole for Candida krusei and Candida glabrata isolates. These methods are not only reliable alternatives to the present reference macrodilution method but are also easy-to-perform and less time-consuming.