A challenge for clinical laboratories: Detection of antifungal resistance in Candida species causing vulvovaginal candidiasis

Abstract

Background: To determine the in vitro susceptibility of vaginal yeasts against 7 antifungals by using 2 different methods and to evaluate if there is a possibility to use disk-diffusion (DD) method in the daily routine. Methods: Eighty-eight vaginal yeasts were tested against 5 antifungal azoles and 2 polyenes, according to Clinical and Laboratory Standards Institute (CLSI) documents DD (M44-A) and broth microdilution (MD) (M27-A3). Results: Resistance was recorded for ketoconazole (KETO), itraconazole (ITR), micoconazole amphotericin B (AMB), and nystatin (NYS). Between DD and MD, higher rates of agreement were observed for AmB (98.9%), voriconazole (VOR) (84.1%), and NYS (77.3%). For the other antifungals, the agreement varied from 34.1% (KETO) to 71.0% fluconazole (FLU). Conclusion: While the DD method may be a useful tool to determine the antifungal susceptibility profile in clinical laboratories in the future, it still requires improvements in its standardization since it was not reliable in detecting resistance in vitro.