Colonies on potato dextrose agar at 25°C are buff to tan initially, usually becoming darker with age. The reverse is centrally dark at maturity. Growth rate is moderate to rapid.
Acrophialophora is similar to Paecilomyces, in that it forms chains of ellipsoidal to fusiform conidia from basally swollen phialides borne either on conidiophores or directly from the vegetative hyphae. The genus is differentiated from Paecilomyces by unbranched, erect, brown, echinulate conidiophores that are fertile only near the apex, by a basal cell anchoring the conidiophores to the vegetative hyphae (similar to a foot cell in the genus Aspergillus), by phialides with a distinct swelling at the base, and by phialides that do not curve or bend away from the main axis. Phialides may proliferate to form secondary openings not delimited by a septum (polyphialides). Conidia are hyaline to pigmented, measure from 4.5-12µm long x 2-6µm wide, and vary in ornamentation from smooth to distinctly spiraled ,.
Acrophialophora fusispora has been reported as the etiologic agent in a brain abscess in a child from Saudi Arabia, and in a case of keratitis from India. It has also been reported in the U.S. under other names as an agent of systemic mycoses involving the brain in a dog, and in a case of human keratouveitis associated with long-term intraocular retention of a contact lens, ,. Additional unpublished reports include two human respiratory cases and disseminated disease in a dog. The species is neurotropic and should be handled in a biological safety cabinet. The long, dark, echinulate conidiophores that form at maturity often appear to have “fallen down” on the plate and give the colony its darker appearance.
FTL* in vitro susceptibility data
|2.0 µg/ml=1||16 µg/ml=1||0.125 µg/ml=1||0.25 µg/ml=2||0.125 µg/ml=1|
* Fungus Testing Laboratory unpublished data (NCCLS M38-A)