Thom, 1918
Macroscopic morphology
Colonies on potato dextrose agar at 25°C are beige to buff to cinnamon. Reverse is yellow and yellow soluble pigments are frequently present. Moderate to rapid growth rate. Colonies become finely granular with conidial production.
Microscopic morphology
Hyphae are septate and hyaline. Conidial heads are biseriate (containing metula that support phialides) and columnar (conidia form in long columns from the upper portion of the vesicle). Conidiophores are smooth-walled and hyaline, 70 to 300µm long, terminating in mostly globose vesicles. Conidia are small (2-2.5 µm), globose, and smooth. Globose, sessile, hyaline accessory conidia (2-6 µm) frequently produced on submerged hyphae.[531, 2202].
Special notes
This species is noteworthy for its refractoriness to amphotericin B therapy [2202, 2203], [1440, 2367] [2152], [891]. Isolates that are initially white and producing only accessory conidia may be mistaken for Histoplasma capsulatum [2202].
FTL* in vitro susceptibility data
| AMB | CAS | ITRA | VORI | POSA | TERB | 5FC | MICA | ANID |
|---|---|---|---|---|---|---|---|---|
| 0.5 µg/ml=1 | 0.03 µg/ml=14 | 0.03 µg/ml=2 | 0.125 µg/ml=2 | 0.03 µg/ml=5 | 0.004 µg/ml=2 | >64 µg/ml=15 | 0.03 µg/ml=6 | 0.03 µg/ml=1 |
| 1.0 µg/ml=6 | 0.06 µg/ml=16 | 0.06 µg/ml=9 | 0.25 µg/ml=22 | 0.06 µg/ml=13 | 0.015 µg/ml=2 | |||
| 2.0 µg/ml=40 | 0.125 µg/ml=37 | 0.125 µg/ml=36 | 0.5 µg/ml=60 | 0.125 µg/ml=9 | 0.03 µg/ml=5 | |||
| 4.0 µg/ml=46 | 0.25 µg/ml=20 | 0.25 µg/ml=20 | 1.0 µg/ml=11 | 0.06 µg/ml=1 | ||||
| 8.0 µg/ml=11 | 1.0 µg/ml=1 | 0.5 µg/ml=2 | 0.125 µg/ml=1 | |||||
| 16 µg/ml=1 | 2.0 µg/ml=2 | 1.0 µg/ml=3 | ||||||
| 4.0 µg/ml=4 |
| Drug/N | AMB/105 | CAS/94 | ITRA/72 | VORI/95 | POSA/27 |
|---|---|---|---|---|---|
| MIC Range | 0.5-8.0 | 0.03-4.0 | 0.03-1.0 | 0.25-1.0 | 0.03-0.125 |
| MIC50 | 4.0 | 0.125 | 0.125 | 0.5 | 0.06 |
| MIC90 | 4.0 | 0.25 | 0.25 | 1.0 | 0.125 |
* Fungus Testing Laboratory unpublished data (NCCLS M38-A)