Evaluation of Virulence factors and antifungal susceptibilities of Candida species isolated from various clinical specimens

Two-hundred of Candida strains were isolated from various clinical specimens which were sent to the microbiology laboratory of Gaziantep University, Medical Faculty, Şahinbey Research Hospital from various clinics and their virulence factors and antifungal susceptibilities were evaluated.Candida strains were identified to species level by using germ tube test, microscopic evaluation on cornmeal-Tween 80 agar, determination of colour of colonies on Candida ID 2 agar and API ID 32C (bioMerieux, France) identification kits. For investigation of proteinase production of Candida strains, bovine serum albumine agar, for phospholipase production egg yolk agar, for esterase activity Tween 80 agar and for slime activity modified tube adherence method were used. The susceptibilities of the strains to amphotericin B, fluconazole, voriconazole, and caspofungin were evaluated by using reference broth microdilution method as described on M27-A3 document of CLSI (Clinical and Laboratory Standards Institute). Additionally, MIC ranges, MIC50 and MIC90 values for each drug were determinated.Of the total 200 Candida strains, 106 (53%) were identified as C.albicans, 49 (24.5%) were C.parapsilosis, 15 (7.5%) were C.tropicalis, 9 (4.5%) were C.krusei, 8 (4%) were C.kefyr, 4 (2%) were C.glabrata, 4 (2%) were C.famata, 3 (1.5%) were C.lusitaniae, and 2 (1%) were C.guilliermondii.For proteinase, 79.2% of C.albicans and 20.2% of non-albicans strains, for phospholipase 95.3% of C.albicans and 1.1% of non-albicans strains, for esterase 96.2% of C.albicans and 34% of non-albicans strains were positive. Proteinase, phospholipase and esterase production of C.albicans strains were higher than non-albicans Candida strains which was statistically significant (p<0.05). For slime activity while 9.4% of C.albicans strains were positive, 51.1% of non-albicans strains were positive, thus slime production of non-albicans strains were higher than that of C.albicans strains (p<0.05).MIC ranges for amphotericin B were determinated as 0.03-1 ?g/mL, for fluconazole 0.125-?64 ?g/mL, for voriconazole 0.03-16 ?g/mL, and for caspofungin 0.015-0.25 ?g/mL. All Candida strains were susceptible to amphotericin B and caspofungin. Thirty-three (16.5%) isolates were resistant to fluconazole, and 12 (6%) isolates were susceptible dose-dependent. Eight (4%) isolates were resistant to voriconazole, and four (2%) isolates were susceptible dose-dependent.As conclusion, when we investigated the relationship between virulence factors and antifungal resistance, we found out that in non-albicans Candida strains there were both significant relationship between esterase activity and voriconazole resistance, and slime production and fluconazole resistance (p<0.05).