Determination and Comparison of Fluconazole Susceptibility by Two Different Microdilution Methods in Candida Strains Isolated from Hospitalized Immunocompromised Patients

Introduction: Clinical and Laboratory Standards (CLSI) Institute recommends CLSI M27-A method as a standard antifungal susceptibility test for Candida strains. The aim of this study was to compare United Kingdom Reference method with CLSI M27-A method. Materials and Methods: Seventy-five Candida species isolated from various clinical samples from the hospitalized, immunocompromised patients were included in the study. Of the 75 Candida strains isolated, 61 (81.3%) were identified as Candida albicans, 6 (8%) as Candida glabrata, 3 (4%) as Candida parapsilosis, 3 (4%) as Candida guilliermondii and 2 (2.7%) as Candida tropicalis. The susceptibility of the identified species to fluconazole was evaluated by two different microdilution methods and the results were compared. For the standard microdilution method (CLSI M27-A) RPMI 1640 medium and for the alternative method (United Kingdom Reference method) Yeast Nitrogen Base Broth were used. Results: When ± 2 difference in minimal inhibitory concentration (MIC) values was used for evalution of agreement between the two media, the percent agreement rate was found as 84%. When ± 1 difference in MIC values was used for evalution of agreement between the two media, the percent agreement rate was found as 68%. Conclusion: United Kingdom Reference method seems as a good alternative testing of antifungal susceptibility for Candida strains