Isolation and characterization of Cryptococcus neoformans var. gattii from samples of Eucalyptus camaldulensis in Mexico city.

The habitat of Cryptococcus neoformans var. gattii is not fully known in Mexico. We investigated the relationship of the yeast with Eucalyptus camaldulensis soil in three main Avenues of the city. A total of 135 trees of the species E. camaldulensis, were selected. Samples were taken in duplicate from the ground containing vegetable debris, tree cortex, leaves and flowers. Isolation of the yeast was made on Guizotia abyssinica media, using Staib technique. The identification was accomplished by biochemical and morphologic tests, and caraterization of the variety was made by bromotimol canavanine-glycine-blue (CGB) and D-proline tests. Isolation of 87 strains of Cryptococcus spp. was acomplished and eight of them were identified as C. neoformans var. gattii. These findings confirmed the close relationship of C. neoformans var. gattii and E. camaldulensis. To our knowledge this is the first report concerning the isolation of this variety from E. camaldulensis trees in Mexico.