Improved auxanographic method for yeast assimilations: a comparison with other approaches.

An improved pour-plate auxanographic method has been developed for determining the assimilation of 14 different carbohydrates by medically important yeasts. Reduction of a dye incorporated into the agar has been correlated with the growth and carbohydrate assimilation of the yeasts, allowing the speciation of many yeasts within 24 to 48 h. This technique has been found to compare more than favorably with existing yeast assimilation techniques, in terms of rapid identification, total cost, and technician time in preparing and inoculating the plates. The dye pour-plate auxanographic technique provides an easier-to-interpret, rapid, and reproducible method of mycological identification for small clinical laboratories.