(described by Cochet ex Sigler and Carmichael in 1976)
Macroscopic morphology
Colonies on Sabouraud dextrose agar at 35°C represent the Trichosporiella yeast synanamorph of Arthrographis kalrae[2106]. These colonies are cream colored and glabrous and, may resemble those of Candida albicans. When grown on potato dextrose agar for 7 day at 25°C colonies are velvety with a white to buff front and a pale yellow reverse.
Microscopic morphology
The yeast phase consists of elongate to oval budding blastoconidia that are germ tube negative. The filamentous phase has hyaline, septate hyphae, dendritic (tree-like) conidiophores, and chains of rectangular arthroconidia 2-4 µm in length not separated by disjunctor (intervening) cells. The vegetative hyphae may also produce sessile, subglobose conidia measuring 4 x 5 µm.
Special Notes
Arthrographis kalrae is frequently mistaken for a Candida species, particularly when young and grown at 35°C. Incubation at 25-30°C is necessary for the filamentous phase to develop. Physiologic features that may assist in the identification include a weakly positive urease test, the ability to grow on media containing cycloheximide, no assimilation of nitrate, and growth at 40-42°C. This organism is a documented etiologic agent of mycetoma[547], photophobia in a contact lens wearer[1764], sinusitis and meningitis in an AIDS patient[435], and sinusitis and ophthalmitis in a healthy individual following trauma to the eye[2461].
FTL* in vitro susceptibility data
| AMB | CAS | ITRA | FLU | KETO | 5FC |
|---|---|---|---|---|---|
| 2.0 µg/ml=1 | 32 µg/ml=1 | <0.015 µg/ml=1 | 16 µg/ml=1 | 1.0 µg/ml=1 | >64 µg/ml=1 |
| 0.125 µg/ml=1 | 32 µg/ml=1 |
| Drug/N | AMB/1 | CAS/1 | ITRA/2 | FLU/2 |
|---|---|---|---|---|
| MIC Range | 2.0 | 32 | <0.015-0.125 | 16-32 |
* Fungus Testing Laboratory unpublished data (NCCLS M38-A)