(Sato) C.E. Skinner (1947b)
Macroscopic morphology
Colonies on Sabouraud dextrose agar at 25°C are pale pink to beige, smooth and mucoid. Occasional isolates are rough and wrinkled.
On cornmeal following 72 hours incubation at 25°C, globose to ovoid yeast cells are formed (3.1-3.0 x 3.5-6.2 µm in diameter). Neither true nor pseudohyphae are formed.
Special notes
This isolate is urease and nitrate positive, with negative growth on cycloheximide or at 40°C. The type strain was isolated from air. The species Cryptococcus albidus is composed of a complex of species as shown by DNA analysis [1270]. This accounts for the variability seen in colony morphology. Of note is the confusion of this isolate with two moulds that initially appear similar in colonial morphology. Both Aureobasidium pullulans and Hormonema dematioides have been mistakenly identified as C. albidus by commercial panels. When yeast ID panels give C. albidus as an identification choice, cultures should be held a minimum of seven days prior to final identification. Colonies of the mould isolates turn dark with the production of dematiaceous arthroconidia. True hyphae and dematiaceous arthroconidia are easily visualized on cornmeal agar preparations. While infections with non-neoformans Cryptococcus species are rare, case reports of infections with C. albidus do appear in the literature. Infections have been reported in cutaneous infection [1619], in the eye and blood of lymphoma patients [808], [1869], and in leukemia patients [2401], [853]. In addition, a case report exists describing a patient with Cryptococcus albidus and mucormycosis empyema [1065]. Susceptibility data, while numbers are small, are consistent between the FTL and that reported by Serena, et. al. [2079].
FTL* in vitro susceptibility data
| AMB | CAS | FLU | ITRA | VORI |
|---|---|---|---|---|
| 0.125 µg/ml=1 | 2.0 µg/ml=1 | 2.0 µg/ml=1 | <0.015 µg/ml=1 | 0.125 µg/ml=2 |
| 0.25 µg/ml=5 | 4.0 µg/ml=1 | 4.0 µg/ml=2 | 0.125 µg/ml=2 | 0.5 µg/ml=1 |
| 0.5 µg/ml=2 | 8.0 µg/ml=3 | 8.0 µg/ml=4 | 0.25 µg/ml=1 | 1.0 µg/ml=2 |
| 16 µg/ml=1 | 16 µg/ml=1 | 0.5 µg/ml=4 | 4.0 µg/ml=1 | |
| 64 µg/ml=3 | 1.0 µg/ml=1 |
| Drug/N | AMB/8 | CAS/6 | FLU/11 | ITRA/9 | VORI/6 |
|---|---|---|---|---|---|
| MIC Range | 0.125-0.5 | 2-16 | 2-64 | <0.015 -1.0 | 0.125 -4.0 |
* Fungus Testing Laboratory unpublished data (CLSI M27-A2)