Microbiology: Candifast Identifies Some Clinical Yeast Isolates, Needs To Improve in Antifungal Susceptibility

Abstract

To evaluate its ability to identify clinical yeast isolates, we compared the Candifast kit (International Microbio, Signes, France) to the API 20C (bioMerieux, Marcy-l Etoile, France) system for 127 isolates representing 8 Candida species; to determine its performance in antifungal susceptibility testing, we compared the Candifast kit to the Etest (AB Biodisk, Solna, Sweden) for 66 isolates. The results obtained from the identification portion of the kit achieved 93% agreement with the API 20C; discrepancies were apparent with Candida tropicalis, in which 8 of 18 (44%) isolates were incorrectly identified as Candida albicans. The antifungal susceptibility results obtained agreed with those of the E-test only in susceptibility to amphotericin; discrepancies between 35% and 80% occurred with flucytosine, ketoconazole, and fluconazole. To be incorporated as a routine test in clinical laboratories, the performance of the Candifast kit should improve in both yeast identification and susceptibility testing.