Identification of yeasts by hydrolysis of amides

We analysed the hydrolysis of 23 amides by 500 yeast and yeast-like strains isolated from clinical specimens, identified to species level by conventional methods, in order to verify the validity of this method of species identification. The results show that 10 of these amides (acetamide, acrylamide, alaninamide, formamide, glycinamide, propionamide, urea, thioacetamide, thiourea and valeramide) are sufficient to differentiate seven genera and 19 species, with an occasional requirement for three additional tests: cycloheximide susceptibility, surface film formation on liquid medium and ascospore formation. The study of the amidase activity in yeasts and yeast-like fungi seems to be a promising method of identifying strains isolated from clinical samples.