In vitro activity of five antifungal agents against Candida albicans isolates, Sari, Iran

Background and Purpose: Candida albicans is the most common causative agent of candidiasis. Candidiasis management is dependent on the immune status of the host, severity of disease, and the choice of antifungal drug. Antifungals, specifically triazoles, are widely administered for the treatment of invasive fungal infections. Herein, we aimed to evaluate the in vitro susceptibility of C. albicans isolates to fluconazole (FLZ), itraconazole (ITZ), voriconazole (VRZ), amphotericin B (AMB), and Caspofungin (CAS). Materials and Methods: A total of 44 clinical strains of C. albicans were collected from 36 patients admitted to four hospitals in Mazandaran Province, Iran. The in vitro antifungal susceptibility testing was performed based on the Clinical and Laboratory Standards Institute methods. Results: Generally, 34 isolates were susceptible to all the five antifungal drugs, while four isolates were susceptible or susceptible dose-dependent (SDD) and six isolates were SDD or resistant to these antifungals. The lowest minimum inhibitory concentration (MIC; 0.016 μg/ml) belonged to AMB and the highest MIC was for FLZ (16 μg/ml). The lowest MIC50 (0.063 μg/ml) was related to ITZ and the lowest MIC90 (0.25 μg/ml) pertained to CAS; in addition, the highest MIC50 (1 μg/ml) and MIC90 (4 μg/ml) were for FLZ. Four of the isolates showed resistance to both FLZ and VRZ, separately, and five isolates were resistant to ITZ. Caspofungin showed potent activity against more than 95% of the C. albicans isolates. Conclusion: Overall, we reported 9.1% resistance to FLZ and VRZ, 11.3% resistance to ITZ and AMB, and 4.6% resistance to caspofungin. Our finding is in agreement with previous observations proposing that C. albicans isolates develop resistance to some antifungal drugs such as FLZ since they are widely used as prophylaxis.