Susceptibility testing of Candida species: comparison of NCCLS microdilution method with Fungitest

Fungitest is a new commercially available and easy-to-perform breakpoint test system using six antifungal agents. We compared this test with a modified standard method described by the National Committee for Clinical Laboratory Standards (NCCLS). One hundred isolates of Candida species were tested with both methods. Based on the same breakpoints, the correlation of qualitative results between the reference method and Fungitest was high. Best results were obtained after incubation of Fungitest for 48 h. Overall agreement was high, an excellent correlation was given with amphotericin B and flucytosine (100% and 99%, respectively), whereas itraconazole showed only 86% concordance. When Fungitest was read after 24 h the agreement was lower ranging from 100% to 75%. Some of the breakpoints used with Fungitest differ from the breakpoints recommended by NCCLS, whereas others have not been elaborated by the NCCLS. The adaptation of Fungitest breakpoints to NCCLS and determination of further breakpoints have to be discussed before Fungitest can be recommended for routine use.