Investigation of antifungal susceptibility of candida species isolated from various clinical samples with disc diffusion method

Increasing frequency of infections due to Candida species in recent years and widespread use of empirical antifungal cause the development of resistant Candida strains and increased resistance rates. Therefore, the need for in vitro antifungal susceptibility tests is increasing in selecting appropriate and effective antifungal treatments. In this study, Candida strains isolated from various clinical specimens from Düzce University Research and Practice Hospital Microbiology Laboratory were typed and their susceptibility to antifungal agents were investigated. Typing of the strains were done by germ tube test and morphological evaluation on corn meal-tween 80 agar. Disc diffusion method was used to determine antifungal susceptibilities of strains. The diameters of the zones were based on the CLSI criteria. According to this study 156 Candida strains were found as 89 (57.1%) C. albicans, 48 (30.8%) C. glabrata, 11 (7.1%) C. tropicalis, 2 (1.5%) C. lusitaniae, 2 (1.3%) C. kefyr, 2 (1.3%) C. parapsilosis and 2 (1.3%) C. guilliermondii. When the antifungal susceptibilities of strains were examined, antifungals with the greatest resistance were detected as ıtraconazole (64.1%); the antifungals with the highest susceptibilities were as caspofungin (98.7%), voriconazole (94.2%), fluconazole (85.3%) and the highest dose dependent susceptibilities were determined as itraconazole (34.6%) and posacanozole (11.5%) respectively. When strains examined at species level, the most resistant species were C. albicans and C. glabrata. The determined mean zone diameters for amphotericin B and flucytosine were 15.29 (± 3) mm, 17.06 (± 9.8) mm respectively. In conclusion, it has been suggested that identification of Candida species for appropriate treatment and antifungal susceptibility testing in Candida species, especially C. albicans and C. glabrata isolates are required. Key words: Yeast fungus, Candida, antifungal susceptibility, disc diffusion.