Comparative evaluation of Fungitest (R), Neo-Sensitabs (R) and M27T-NCCLS broth microdilution methods for antifungal drug susceptibility testing of Candida species and Cryptococcus neoformans

Two commercial antifungal susceptibility testing systems (Fungitest(R) and Neo-Sensitabs(R)) were compared with the M27T-NCCLS reference broth microdi lution method using one hundred isolates of Candida sp. and Cryptococcus ne oformans. Six different antifungal drugs were tested: amphotericin B, 5-flu orocytosine, fluconazole, itraconazole, ketoconazole and miconazole. The ov erall agreement between the Fungitest and the reference methods was much be tter than between the Neo-Sensitabs and the reference methods: the agreemen t for the Fungitest ranged from 100% for amphotericin B to 76.7% for itraco nazole whereas for the Neo-Sensitabs, it ranged from 90.4% for amphotericin B to 36% for ketoconazole. For the total number of tests performed with Ne o-Sensitabs, there were 37.8% of discrepancies with the reference method wh ereas for the tests performed with Fungitest, there was only 16.5% of discr epancies. Major discrepancies, defined as results that classified an isolat e as susceptible by one method and resistant by another, occurred in 21 cas es for the Neo-Sensitabs test and only in four cases with the Fungitest, na mely 0.6% of the cases. We conclude that the Fungitest method constitutes a simple and reliable procedure for antifungal drug susceptibility testing.