Journal of Krishna Institute of Medical Sciences University (Jan 2018)
Comparison of the VITEK 2 Yeast Antifungal Susceptibility Testing with CLSI Broth Microdilution Reference Method for Testing Four Antifungal Drugs against Candida species Isolated from Blood Samples
Abstract
Background: Although the patients in the Intensive Care Unit (ICU) are at risk for candidemia resulting in complication, rapid diagnosis of aetiologic agent will reduce the delay in initiating the appropriate therapy with adequate dosage of antifungals thus improving the outcome. Due to reduced susceptibility of nonalbicans Candida species to antifungal agents; testing the antifungal susceptibility pattern has become important both epidemiologically and for patient management. Aim and Objectives: To compare the VITEK 2 Yeast antifungal susceptibility testing with Clinical and Laboratory Standards Institute (CLSI) Broth Microdilution (BMD) reference method against isolates of Candida species and assess the Categorical Agreement (CA) and errors. Material and Methods: Candida species isolated from blood samples of patients admitted under Medical and Surgical ICU of Krishna Hospital and Medical Research Centre, Karad were subjected to antifungal susceptibility testing by CLSI reference BMD and VITEK 2 method. Results: Compared to the reference BMD method, the VITEK 2 system yielded highly reproducible and accurate MIC results and excellent overall categorical agreement at 100% for amphotericin B, flucytosine, fluconazole, and voriconazole against C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. lusitaniae and C. guillermondii except C. rugosa and C. glabrata. Conclusion: The VITEK 2 method demonstrated excellent reproducibility and standardization. It provides a fully automated method for fungal identification, determining the MICs against Candida spp. based on spectrophotometry, thus eliminating the inherent bias of manual MIC determination.
