COMPARISON OF BROTH MACRODILUTION, BROTH MICRODILUTION, AND E-TEST ANTIFUNGAL SUSCEPTIBILITY TESTS FOR FLUCONAZOLE

A comparison of the E test, the broth microdilution test, and the refe rence broth macrodilution susceptibility test of the National Committe e for Clinical Laboratory Standards for fluconazole susceptibility tes ting was performed with 238 clinical isolates of Candida species and T orulopsis (Candida) glabrata. An 80% inhibition endpoint MIC was deter mined by the reference broth macrodilution method after 48 h of incuba tion. The MICs obtained by the two study methods were read after 24 an d 48 h of incubation. Overall, excellent agreement within 2 doubling d ilutions was obtained between the broth microdilution and the broth ma crodilution methods for the combined results for all species at both 2 4 h (93%) and 48 h (94%). The correlation of 24-h MIC endpoints betwee n the E test and the broth macrodilution methods was 37% for T. glabra ta, 56% for Candida tropicalis, 93% for Candida albicans, and 90% for other Candida species. The percent agreement at 48 h ranged from 34% f or T. glabrata to 97% for Candida species other than C. albicans and C . tropicalis. These initial results support the further evaluation of the E test as an alternative method for fluconazole susceptibility tes ting of Candida species.