Evaluation of the E test for antifungal susceptibility testing of Candida glabrata

The E test was compared to the reference NCCLS broth macrodilution method for susceptibility testing of Candida (Torulopsis) glabrata. The MICs of amphotericin B, flucytosine, fluconazole and itraconazole were determined using the appropriate culture media (RPMI 1640 agar with 2% glucose, Casitone agar or Antibiotic Medium 3 agar) according to the drug tested. Agreement between the two methods was within plus/minus two dilutions for 77-100% of test results, according to the drug/medium combination. The study revealed problems in determining the MICs of azoles using the E test, and confirmed the suitability of Casitone agar for susceptibility testing of fluconazole even if results were read within 24 h.