A-327 Rapid Antifungal Susceptibility Testing System for Yeasts Based on Fast Cell Growth

Abstract Background Due to the growing burden of fungal infections and a recent rise in antifungal resistance, antifungal susceptibility testing (AFST) is of increasing importance. The common methods of AFST for yeasts have turnaround times of 24 to 48 h. Given the urgency of adequate antifungal treatment in invasive mycoses, rapid antifungal susceptibility testing is urgently needed in clinics to treat invasive fungal infections with the appropriate antifungal drugs and to slow the emergence of antifungal resistance. Methods Here, we demonstrate a rapid AFST by measuring the metabolism in fungal cells using resazurin and a medium that promotes the growth and metabolism of fungal cells (Fig). A total of 32 clinical fungal strains were randomly analyzed from the Peking Union Medical College Hospital. Species of these strains were commonly found in patients with systemic infections, including 9 Candida albicans, 5 Candida krusei, 3 Candida tropicalis, 3 Candida parapsilosis, 3 Candida lusitaniae, 7 Candida glabrata, and 2 Candida guilliermondii. The Sensititre YeastOne panel was performed according to the manufacturer*s instructions as reference methods. For the rapid AFST method, MICs were determined at 6 h of incubation. MICs for the YeastOne panel were read at 24 h of incubation. The overall agreement within +/- 2 dilutions by both methods was calculated against ten antifungal agents. Results Considering the Sensititre YeastOne Colorimetric Broth method as a comparator method, ten antifungal agents (?uconazole, itraconazole, voriconazole, posaconazole, isavuconazole, caspofungin, micafungin, anidulafungin, amphotericin B, and 5-flucytosine) showed an essential agreement of > 90%. Conclusion Therefore, this rapid AFST can be considered as an optional method that can obtain results and interpretations faster than previous methods. This method overcomes the limitation of slow growth in conventional methods and has the potential for the rapid diagnosis of candidemia and other clinical fungal infections.