Antifungal susceptibility testing using the E test: comparison with the broth macrodilution technique.
The National Committee for Clinical Laboratory Standards reference broth macrodilution method for antifungal susceptibility testing was compared with the E test by testing 86 clinical isolates of Candida spp. and Cryptococcus neoformans. The MIC agreement rates for the two methods for Candida spp. were 73-89% within +/-1 doubling dilution and 87-100% within +/-2 dilutions. For C. neoformans, agreement within +/-1 dilution was > 70% for all the agents tested except fluconazole for which agreement was 35%. Our data support the further evaluation of the E test as an alternative method for antifungal susceptibility testing. However, E test MICs of fluconazole for C. neoformans, particularly C. neoformans var. gattii should be interpreted with caution, as falsely elevated MICs may occur.
Chen
S C
SC
Department of Clinical Microbiology, Westmead Hospital, New South Wales, Australia.
O'Donnell
M L
ML
Gordon
S
S
Gilbert
G L
GL
D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D003455:Cryptococcus neoformans / Q000187:drug effects*; D003470:Culture Media; D015725:Fluconazole / Q000494:pharmacology; D017964:Itraconazole / Q000494:pharmacology; D007654:Ketoconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000379:methods*; D015203:Reproducibility of Results
D000935:Antifungal Agents; D003470:Culture Media; D017964:Itraconazole; D015725:Fluconazole; D007654:Ketoconazole