In vitro susceptibility of Candida dubliniensis to current and new antifungal agents

Background: Candida dubliniensis is a recently described Candida species cl osely related to Candida albicans, which has been associated with oral cand idiasis in HIV-infected patients. Fluconazole-resistant strains of C. dubli niensis are easily obtained in vitro and this fact could be a complication if this resistance develops during treatment with this drug. Methods: In th e present study, the in vitro antifungal susceptibilities of 36 C. dublinie nsis clinical isolates and culture strains to current a nd new antifungal a gents, such as amphotericin B (AMB), amphotericin B lipid complex (ABLC), a mphotericin B colloidal dispersion (ABCD), 5-fluorocytosine (5FC), fluconaz ole (FLC), itraconazole (ITC), ketoconazole (KTC), liposomal amphotericin B (LAMB), liposomal nystatin (LNYT), LY303366 (LY), SCH56592 (SCH), and vori conazole (VRC), were determined according to the National Committee for Cli nical Laboratory Standards M27-A broth microdilution method for yeasts. Res ults: Most isolates of C. dubliniensis were susceptible to both new and cur rent antifungal drugs, with 75.9% isolates susceptible to KTC, 86.2% to FLC and to ITC, and similar to 100% to the other antifungal agents tested. The cross-resistance phenotypes are detailed. Four isolates were resistant (MI C greater than or equal to 64 mug/ml) to FLC. These 4 isolates were also re sistant to KTC, and 3 of them were also resistant to ITC (MIC 11 mug/ml for both agents). However, these isolates were highly susceptible to 5FC and a ll polyene formulations (AMB, ABLC, ABCD, LAMB, and LNYT), triazole (SCH an d VRC) and echinocandin (LY) antifungal agents. Conclusion: The new liposom al and lipidic formulations of AMB, LNYT, and the new triazoles and echinoc andins may provide new alternatives to FLC for the treatment of infections by C. dubliniensis. Copyright (C) 2000 S. Karger AG. Baser.