A simple disk-diffusion test for differentiation of yeast species.

A disk-diffusion method for identification of yeasts was developed that depended on their different but distinct susceptibilities to the following chemicals: janus green, ethidium bromide, 2, 3, 5-triphenyltetrazolium chloride, brilliant green, cycloheximide and rhodamine 6G. For 594 of 623 routinely isolated yeasts, the disk-diffusion and the commercial API 20C auxanogram tests gave the same identification, an agreement of 95.3%. Only 8 of 1052 isolates from clinical specimens were not identified by the disk-diffusion method. The method is simple, inexpensive and technically straightforward and for most isolates gives an identification in 24 h.