Performance evaluation of Vitek 2 AST-YS08 for antifungal susceptibility testing of yeast: a categorical agreement study with Liofilchem mic strips with 22 clinical samples in Hospital Sultanah Aminah, Johor Bharu and Hospital Pakar Sultanah Fatimah, Muar

Abstract

Invasive fungal infections caused by Candida spp. and Cryptococcus neoformans present significant clinical challenges. This study evaluates the Vitek 2 AST-YS08 system against Liofilchem MIC strips to determine minimal inhibitory concentrations (MICs) of fungal agents in two hospitals in Johor. A total of 22 clinical isolates from Candida spp. and Cryptococcus neoformans were tested. MIC values for antifungals were determined via the Vitek 2 system and Liofilchem MIC strips. Results were compared for concordance using the latest Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. The Vitek 2 system demonstrated an overall categorical agreement of 91% with MIC strips. Categorical agreements were achieved for all isolates of C. albicans, C. parapsilosis, C. guilliermondii, and Cryptococcus neoformans. Lower concordance rates were observed for C. tropicalis (80%) and C. glabrata (75%). Two discrepancies were identified in Sample 5 (C. glabrata), micafungin MIC values differed between systems (0.006 μg/mL vs. 0.12 μg/mL), and in Sample 16 (C. tropicalis), fluconazole MIC values varied (1 μg/mL vs. 8 μg/mL). The Vitek 2 method provides quick results and matches well with manual testing. The discrepancy of the results with different methods may affect the treatment outcome for the patient. The system's automation and efficiency make it a valuable tool for high-throughput clinical microbiology laboratories. The Vitek 2 AST-YS08 system is a fast and reliable way to test the antifungal sensitivity of yeast. More studies are needed to improve its use in different medical situations.