Rapid identification of yeasts by semi-automated and conventional methods

Five different methods for the identification of significant yeast from clinical specimens were compared for their reliability, rapidity and cost-effectiveness. Three commercial methods consisted of semi-automated Abbott's yeasts identification system using MS-2 (Abbott Laboratories, Diagnostic Division, Irving, Texas), API 20C (Analytab Products, Inc., Plainview, NY) and Uni-Yeast-Tek (Flow Labs, Inc., MacLean, VA). Two conventional methods included the modified dye-plur plate auxanographic and rapid tube assimilation method. The 242 coded clinical isolates used in this study included 20 species of Candida, Cryptococcus, Saccharomyces Geotrichum, Rhodotorula, Torulopsis and Trichosporon. The identification accuracies with all the systems ranges between 92.3% to 97.5%. Results were available with Abbott's MS-2 within 24 h, with rapid tube assimilation method in 6-48 h and in 72 h with other systems. Rapid tube assimilation and dye-pour-plate auxanographic methods were least expensive, with labour and material costing around $1.00 per identification, whereas the commercial system cost a little over $5.00.