FLUCONAZOLE SUSCEPTIBILITY TESTING OF CANDIDA SPECIES BY DISC DIFFUSION AND AGAR DILUTION METHOD

Fungal infections with candida species are an important cause of morbidity and mortality(1). Situation is further worsened by increasing resistance to antifungal drugs(2). The objective of this study was to evaluate antifungal susceptibility pattern of Candida species to fluconazole by disc diffusion and agar dilution method and compare these two methods as far as fluconazole is concerned. MATERIAL & METHODS: Between January 2006 to December 2006, 119 Candida species were isolated from 225 sputum samples of patients of pulmonary tuberculosis and immunocomprised patients. RESULTS: Of the 119 Candida isolates 33 (27.73%) were Candida albicans, 32 (26.89%) were Candida gullermondi, 27 (22.68%) Candida tropicalis, 14 (11.76%) Candida pseudotropicalis, 7 (5.88%) Candida parapsilosis and 6 (5.04%) were Candida krusei. The Candida isolates were tested for fluconazole by disc diffusion method on Muller hinton agar with 2% glucose and 0.5 microgram of methylene blue(3). Amongst the 119 Candida isolates, 17 (14.28%) isolates were resistant to fluconazole by disc diffusion method. MIC done by agar dilution method using CLSI guidelines(4). Candida isolates showed growth of 15 (88.23%) Candida strains upto 8 microgram/ml with 80% inhibition of growth whereas 2 (1.7%) isolates showed MIC upto 64 microgram/ml. CONCLUSIONS: Candida albicans though a common species other species were isolated in significant number. The results of disc diffusion for fluconazole do not correlate with agar dilution method. To cater the need of resource constrained laboratories, it is important to have results that correspond to the clinical outcome of antifungal treatment and show co-relation to those obtained with the reference method as recommended by CLSI guidelines and also be reproducible(5). Further critical studies are needed.