U.S. Government's Occupational
Safety and Health Administration [OSHA]
the following as the health effects of Acremonium mold:
Irritant, Hypersensitivity pneumonitis, Dermatitis.
showing long awl-shaped phialides producing cylindrical,
one-celled conidia mostly aggregated in slimy heads at the apex of
Colonies are usually slow growing, often compact and
moist at first, becoming powdery, suede-like or floccose with age,
and may be white, grey, pink, rose or orange in color.
Hyphae are fine and hyaline and produce mostly simple
awl-shaped erect phialides. Conidia are usually one-celled (ameroconidia),
hyaline or pigmented, globose to cylindrical, and mostly aggregated
in slimy heads at the apex of each phialide.
This genus is distinguished from hyaline isolates of Phialophora
by the absence or very limited development of a collarette on the
phialide and the predominant formation of well differentiated,
awl-shaped phialides with a basal septum. Microconidial Fusarium
isolates may be confused with Acremonium, but they usually
grow faster and have colonies with a characteristic fluffy
For identification, potato dextrose
agar and cornmeal agar are the most suitable media to use and
exposure to daylight is recommended to maximize culture color
and Natural Habitats
species. are filamentous, cosmopolitan fungi commonly isolated from plant
debris and soil. The sexual state of Acremonium is not
well-defined. Thus, it is classified among the deuteromycetes group of
fungi by some authorities. Others prefer to include it in Ascomycota
phylum, due to its structural properties similar to those of this group.
According to The
Vol. 3, No. 9, “Acremonium species is primarily isolated from
soil, plant debris, foodstuffs, hay, rotting mushrooms, and indoor
building materials, such as the acoustic and thermal fiber glass
insulation used in heating ventilation and air conditioning system.
Acremonium has a high water affinity of Aw 0.90-0.98 and is often
isolated from cooling coils, drain pans, window seals, and water from
humidifiers. Additionally, Acremonium
is occasionally found growing with
Stachybotrys. The spores of this fungus
are formed in a slimy mass resulting to a limited aerosolization.”
The genus Acremonium currently contains 100 species, of
which most are saprophytic, being isolated from dead plant material and
There are three
main species of Acremonium implicated in infections: Acremonium
falciforme, Acremonium kiliense, and Acremonium recifei.
Pathogenicity and Clinical Significance
is considered as one of the causative agents of white grain mycetoma. In
addition to some cases of onychomycosis due to Acremonium, cases of
endocarditis, endophthalmitis, keratitis, meningitis, and peritonitis have
also been reported. This fungus is known to cause opportunistic
infections mainly among the immunocompromised patients, such as bone
marrow transplant recipients.
species are encountered as contaminants as well thus; their isolation in
culture requires careful evaluation. Additionally, some Acremonium
species are even parasitic toward other fungal organisms which are generally
termed as mycoparasites.
Growth rate is moderately rapid and colonies are compact, flat or folded
and occasionally raised in the center; initially, texture is glabrous,
velvety and membrane – like and becoming cottony with age due to the
overgrowth of loose hyphae;
Colonies are observed having diameter measuring from 1 to 3 cm after seven
days of incubation at 25°C; and
Surface colony color ranges from white, to pale gray or pale pink while the
reverse is uncolored or a pink to rose colored - pigmentation may be
hyaline and septate which are characteristically fine and narrow;
Phialides are erect, unbranched and solitary which arise directly from the
hyphal tips; phialides are separated by a septum from the hyphae and taper
towards their tips; and
Conidia are hyaline, may be unicellular or multicellular, fusiform – shaped
with a slight curve or may look like a shallow crescent, appear in clusters,
in balls or as fragile chains rarely, with size of 2 – 3 x 4 – 8 µm, and are
found at the tips of the phialides; the structural properties of the conidia
may vary depending on the species.
Table 1. Structural Differences of Conidia of Acremonium species
Structural Differences of Conidia
Produces crescent - shaped, non -septate conidia, 2 -
or 3 - celled conidia may also be observed sometimes
Produces short straight conidia
Produces usually crescent – shaped and non – septate
“The wet conidial
spores are disseminated mechanically by insects or water droplets.
Occasionally, spores from old growth are wind disseminated,” according to
Reporter, Vol. 3, No. 9
is not easily identified due to their very small, colorless and non –
distinctive spores. Furthermore, some spores are so small that they may be
obscured by background debris. Air sampling cultures are a better way to
recover and identify airborne
can easily be identified on direct examination as it is possible to view
distinctive chains or the slimy heads of conidia.
Acremonium species are cosmopolitan nature, they are also
encountered as contaminants. Thus isolation in culture requires cautious
Reported data on
in vitro susceptibility are very limited. The novel azoles,
posaconazole and voriconazole show favorable in vitro activity
against Acremonium strains.
On the other hand, in vivo
response largely depends on both antifungal therapy and surgical
remains as the mainstay of therapy among the available antifungal agents.