A Com par i son of Methods for Yeast Iden ti fi ca tion In clud ing CHROMagar Candida, Vitek Sys tem YBC and a Tra di tional Bio chem i cal Method

Back ground. CHROMagar Candida (CAC) is a new chromogenic me dium for the pre sump tive iden ti fi ca tion of clin i cally-important yeast iso lates. A yeast bio chem i cal card (YBC), a part of the Vitek sys tem is an au to matic method for the iden ti fi ca tion of clin i cally-important yeast iso lates. We con ducted a com par i son of these two meth ods with a tra di tional bio chem i cal method in or der to choose a rapid and ac cu rate tech nique for yeast iden ti fi ca tion. Methods. All yeast iso lates were in oc u lated onto Sabourand dex trose agar (SDA) and CAC, and in cu bated at 30 °C for 48 hours. All iso lates were si mul ta neously tested us ing tra di tional bio chem i cal meth ods and the yeast bio chem i cal card from the Vitek sys tem. Re sults. We eval u ated 235 yeast iso lates from clin i cal spec i mens, in clud ing 89 Candida albicans, 47 Candida tropicalis, 43 Candida gla brata, six Trichosporon beigelii, and five Candida krusei in ad di tion to 45 iso lates of other yeast spe cies. Iso lates were pre sump tively iden ti fied on the ba sis of col ony color and ap pear ance on CAC me dium. These ob ser va tions were com pared with a tra di tional bio chem i cal yeast- identification method and also with YBC from the Vitek sys tem. For five com monly-isolated spe cies (Candida albicans, Candida trop icalis, Candida glabrata, Candida krusei and Trichosporon beigelii), agree ment among the CAC me dium, YBC method and tra di tional bio chem i cal method were 98.9% (187/189), 96.3% (182/189), 100% (189/189), re spec tively. Con clu sions. From our com par i son, the CAC me dium is a con ve nient and eco nomic method to iden tify five com monly-noted yeast spe cies, and the YBC method war rants a greater cost and re quires a lon ger pe riod of time to ob tain re li able re sults. [Chin Med J (Tai pei) 2001;64:568-574]