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.

摘要

Background: Although the patients in the IntensiveCare Unit (ICU) are at risk for candidemia resulting incomplication, rapid diagnosis of aetiologic agent willreduce the delay in initiating the appropriate therapywith adequate dosage of antifungals thus improvingthe outcome. Due to reduced susceptibility of nonalbicansCandida species to antifungal agents; testingthe antifungal susceptibility pattern has becomeimportant both epidemiologically and for patientmanagement. Aim and Objectives: To compare theVITEK 2 Yeast antifungal susceptibility testing withClinical and Laboratory Standards Institute (CLSI)Broth Microdilution (BMD) reference method againstisolates of Candida species and assess the CategoricalAgreement (CA) and errors. Material and Methods:Candida species isolated from blood samples ofpatients admitted under Medical and Surgical ICU ofKrishna Hospital and Medical Research Centre, Karadwere subjected to antifungal susceptibility testing byCLSI reference BMD and VITEK 2 method. Results:Compared to the reference BMD method, the VITEK 2system yielded highly reproducible and accurate MICresults and excellent overall categorical agreement at100% 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 demonstratedexcellent reproducibility and standardization. Itprovides a fully automated method for fungalidentification, determining the MICs against Candidaspp. based on spectrophotometry, thus eliminating theinherent bias of manual MIC determination.