Enzymatic profile of Cryptococcus neoformans strains by using the API-ZYM system.

Determination of the enzymatic profile of 41 Cryptococcus neoformans strains, 20 isolated from AIDS patients and 21 from bird droppings, was performed by using the API-ZYM commercial kit system (Bio-Mérieux, France), which tests 19 different kinds of enzymes. All the strains showed positive enzymatic activity to the esterase (C4) (n. 3). On the contrary, alkaline phosphatase (n. 2), cystine arylamidase (n. 8), trypsin (n. 9), chymotripsin (n. 10), alpha-galactosidase (n. 13), beta-glucuronidase (n. 15), alpha-mannosidase (n. 19), alpha-fucosidase (n. 20) were negative in all the strains. The other 10 enzymes (n. 4,5,6,7,11,12,14,16,17,18) were distributed among the strains in different positive percentages. From the results of each enzymatic profile obtained, the 20 AIDS strains were grouped into 15 types, while the 21 bird dropping strains were grouped into 14 types. Interestingly, only one enzyme profile type occurred in the strains isolated from the AIDS patients and from the bird droppings. These results suggest that the API ZYM system is useful in discriminating between the AIDS strains and the bird dropping strains.