Extracellular enzymatic activity in 11 Cryptococcus species

The extracellular enzymatic activity of 36 strains of yeast belonging to 11 species of the genus Cryptococcus, has been investigated, using the API-ZYM (BioMérieux, France) commercial system, with the objective of determining the differences in the enzymatic profiles of the various species. The strains studied were: 9 of C. neoformans, 7 of C. albidus, 6 of C. laurentii, 5 of C. uniguttulatus, 3 of C. humicolus, and 1 each of C. ater, C. curvatus, C. dimennae, C. hungaricus, C. infirmo-miniatus and C. magnus. All the strains showed enzymatic activity with positivity to Phosphatase alkaline, Esterase lipase C8, Leucine arylamidase, Phosphatase acid and Naphthol-AS-BI-phosphohydrolase, and negativity to Lipase C14, Trypsin, Chemotrypsin, beta-galactosidase, beta-glucuronidase and alpha-manosidase. Variable enzymatic activity was shown to Esterase C4, Valine arylamidase, Cystine arylamidase, alpha-galactosidase, alpha-glucosidase, beta-glucosidase, N-acetyl-beta-glucosaminidase and alpha-fucosidase. This allowed 11 separate enzymatic patterns to be established. The species C. neoformans and C. laurentii each presented two distinct patterns; C. uniguttulatus, C. hungaricus and C. magnus shared the same pattern; C. albidus, C. ater, C. curvatus, C. dimennae, C. humicolus and C. infirmo-miniatus presented an individual enzymatic pattern. The results obtained suggest that the API-ZYM system could be useful for the identification of species of the genus Cryptococcus and for the differentiation of the enzymotypes for epidemiological purposes.