Caspofungin-Non-Susceptible Candida orthopsilosis Isolated from Onychomycosis in Iran.

BACKGROUND: Although Candida albicans remains the most common fungal isolate from clinical specimens, many studies have detected a shift towards non-albicans Candida species. Despite worrying clinical pictures associated with latter species , there is little information regarding its susceptibility patterns against currently available antifungal agents, with only a small number of strains having been studied.

METHODS: We evaluated the in vitro antifungal susceptibilities of clinical isolates of C. orthopsilosis already identified by two-steps PCR-RFLP and reconfirmed by sequence analysis of entire ITS rDNA region, to six antifungal drugs.

RESULTS: The resulting MIC50 and MIC90 for all strains (n=18) were in increasing order, as follows: posaconazole (0.016 & 0.063 μg/ml); itraconazole (0.031 & 0.125 μg/ml); amphotericin B (0.5 & 1 μg/ml); fluconazole (0.25 & 0.5 μg/ml) and caspofungin (4 & 8 μg/ml). A uniform pattern of the MIC ranges was seen for amphotericin B, fluconazole, itraconazole, and posaconazole, while a widest range and the highest MICs were observed for caspofungin.

CONCLUSION: Although we emphasis on the careful species designation of the clinical isolates of Candida , the antifungal susceptibility patterns of these clinically important organisms may have an application in clinical and epidemiological setting and deserve the implementation of local surveillance programs to monitor.