A new genus, filobasidiella, the perfect state of Cryptococcus neoformans.

In 1966, Shadomy and Utz (2) reported hyphal formation in a few strains of Cryptococcus neoformans, a pathogenic yeast. Shadomy (1) later observed clamplike connections in the hyphae-forming isolates similar to those produced in basidiomycetes. On the basis of such observations and the fact that all basidiomycetous yeasts belong to heterobasidiomycetes, she has proposed that C. neoformans be placed in the genus Leucosporidium of the Ustilaginaceae. Recently I have cultured 15 strains of C. neoformans isolated from different clinical specimens on malt extract and sporulation agar (3) in various pairs. A basidiomycetous state was found in four pairs after a total of 3 wk of incubation, 1 wk at 25 C, and 2 wk at 15 C. Sexual reproduction was initiated by conjugation of two yeast cells which was followed by the formation of hyphae with clamp connections. A group of long basidia (FIG. 1) each having a subglobose to flask-shaped apex with sessile basidiospores was produced terminally or laterally from the hyphae. In contrast to Leucosporidium, teliospores were lacking; the basidia were never septate and produced terminal basidiospores. Basidial structures of C. neoformans showed a close relationship with Filobasidium Olive (4) in the monogeneric family Filobasidiaceae Olive (3) of the Ustilaginales. However, there are enough differences in the manner of basidiospore formation to warrant description of a new genus. Formation of basidiospores in species of Filobasidium is not repetitious, whereas the new basidiomycete forms basidiospores in basipetal chains by repetitious budding. 1197