Evaluation of the E test system versus a microtitre broth method for antifungal susceptibility testing of yeasts against fluconazole and itraconazole.

The E test strip (AB Biodisk, Solna, Sweden) as an antimicrobial susceptibility testing method is a new and promising tool with broad application in microbiology. This method is less labour intensive than broth dilution methods and may be useful for testing individual clinical isolates. In contrast to several publications comparing E test antibacterial strips with NCCLS reference methods, there is little information about the performance of E test antifungal strips. This study compared fluconazole and itraconazole MICs obtained by E test with a microbroth dilution method performed to NCCLS guidelines. Fluconazole and itraconazole E test results exhibited good correlation with the broth microdilution (82% and 81% agreement within +/- 1 two-fold dilution, respectively). The E test is easy to perform and generates MICs for Candida species in 24 h.