Molecular Epidemiology and Antifungal Susceptibility of Candida Species Isolated from Urine Samples of Patients in Intensive Care Unit

The aims of this study were to analyse the amphotericin B and fluconazole susceptibility and molecular epidemiology of Candida strains (Candida albicans, Candida tropicalis and Candida glabrata) isolated from the urine samples of patients hospitalized in the intensive care unit. Identification of the isolates was done according to microscopic morphology (chlamydospor, blastospor, pseudohyphae and true hyphae) on cornmeal agar, germ tube formation and carbohydrate assimilation patterns (API ID 32C bioMerieux, France). Antifungal susceptibilities of the isolates were determined by in vitro broth microdilution method recommended by Clinical and Laboratory Standards Institute (CLSI). To investigate the clonal relationship of the isolates, randomly amplified polymorphic DNA (RAPD) analysis was performed by using Cnd3 primer. Of the 56 Candida isolates minimum inhibitory concentration (MIC) ranges, MIC50 and MIC90 values for amphotericin B were 0.125-1 mu g/ml, 0.125 and 0.5 mu g/ml for C.albicans, 0.125-1 mu g/ml, 0.25 and 1 mu g/ml for C.tropicalis and 0.125-1 mu g/ml, 0.25 and 1 mu g/ml for C.glabrata, respectively. Fluconazole MIC ranges, MIC50 and MIC90 values were 0.25-4 mu g/ml, 0.25 and 0.5 mu g/ml for C.albicans, 0.25-16 mu g/ml, 0.5 and 1 mu g/ml for C.tropicalis and 0.5-64 mu g/ml, 8 and 16 mu g/ml for C.glabrata, respectively. For amphotericin B, none of the isolates had high MIC values (MIC > 1 mu g/ml). While one of the C.glabrata isolates was resistant to fluconazole (MIC >= 64 mu g/ml), one C.tropicalis and two C.glabrata isolates were dose-dependent susceptible (MIC: 16-32 mu g/ml). The results of RAPD analysis indicated an exogenous spread from two clones for C.albicans, one clone for C.glabrata and one clone for C.tropicalis. This study underlines the importance of molecular epidemiological analysis of clinical samples together with hospital environmental samples in terms of Candida spp. to determine the exogenous origin for the related strains and to prevent nosocomial Candida infections.