(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

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* Fungus Testing Laboratory unpublished data (NCCLS M38-A)