Antifungal Susceptibilities of Candida Isolates Causing Bloodstream Infections at a Medical Center in Taiwan, 2009-2010

Abstract

ABSTRACTWe used the Sensititre YeastOne (SYO) method (Trek Diagnostic Systems) to determine the MICs of nine antifungal agents against 474 nonduplicate bloodCandidaisolates. The MIC results were interpreted according to updated clinical breakpoints (CBPs) recommended by the Clinical and Laboratory Standards Institute (CLSI; document M27-S4) or epidemiology cutoff values (ECVs). The rates of fluconazole susceptibility were 99.2% (234/236) inCandida albicans, 86.7% (85/98) inC. tropicalis, and 97.7% (42/43) inC. parapsilosis. Among the 77 isolates ofC. glabrata, 90.9% showed dose-dependent susceptibility (S-DD) to fluconazole. Nearly all isolates ofC. albicans,C. parapsilosis, andC. kruseiwere susceptible to voriconazole; however, rates of voriconazole susceptibility were 78.6% inC. tropicalis. Few isolates ofC. albicans(n= 5; 2.1%) andC. glabrata(n= 3; 3.9%), no isolates ofC. parapsilosis,C. krusei, andC. guilliermondii, but 62.2% (n= 51) ofC. tropicalisisolates were non-wild type for posaconazole susceptibility. For itraconazole susceptibility, 98.3% ofC. albicansisolates were wild type, and 3.9% (n= 3) ofC. glabrataisolates were non-wild type. Almost all of the isolates tested (>97% for all species) were susceptible to both micafungin and anidulafungin. All isolates tested were found to be wild type for amphotericin B susceptibility, with MICs of <1μg/ml. Further evaluation is needed to establish CBPs of antifungal agents by the 24-h SYO method for the management of patients with candidemia or other invasive candida infections.