is a cosmopolitan filamentous fungus which is isolated from soil and
decaying plant material and often associated in decay of food products and
cosmetics. Certain species of Paecilomyces parasitize insects.
Paecilomyces is usually considered as a contaminant as well as a rare
pathogenic fungus in humans.
Paecilomyces contains several species. The most common are
Paecilomyces lilacinus and Paecilomyces variotii. The colony
morphology and microscopic features of the different Paecilomyces
species aid in distinguishing the species from one another.
Thermophilicity is another helpful feature that helps in species
identification. Paecilomyces crustaceus and Paecilomyces
variotii are both thermophilic and grow well at temperatures as high
as 50°C and possibly at 60°C.
Pathogenicity and Health Effects
species can cause various infections in humans which are referred to as
paecilomycosis. The infection ranges from corneal ulcer to
to endophthalmitis which is due to the growth of Paecilomyces
following an extended contact lens use or ocular surgery. Additionally,
Paecilomyces is among the emerging causative agents of
opportunistic mycoses in immunocompromised hosts wherein direct cutaneous
inoculation may lead to these infections and may involve almost any organ
or system of human body. Other infections which have been reported due
to Paecilomyces include soft tissue, pulmonary, and cutaneous
peritonitis, and catheter - related
Paecilomyces species can also cause allergic alveolitis which is an
Furthermore, Paecilomyces can cause infections in animals as well
such as hyalohyphomycosis in cats, laboratory rats, turtles, and goats.
Growth rate is rapid and colonies are flat, powdery or velvety in texture
and mature within three days;
surface colony color is initially white becoming yellow, yellow – green,
yellow – brown, olive – brown, pink, or violet, depending on the species
while reverse is dirty white, buff or brown; and
sweet aromatic odor may be observed with older cultures.
Septate hyaline hyphae, conidiophores, phialides, conidia, and
chlamydospores are present;
Conidiophores are often branched and carry the
phialides at their tips,
and with size ranging from 3 – 4 x 400 - 600 µm;
Phialides are thin, swollen at their bases, elongated at their tips, and
are usually grouped in brush – like structures at the ends of the
Conidia are oval to fusoid in shape, unicellular, hyaline to darkly
colored, smooth or rough, and appear in long chains; and
Chlamydospores are sometimes present.
precautions are required, no special safety measures needed.
Limited data are
available. Data on Paecilomyces fumosoroseus, Paecilomyces
javanicus, Paecilomyces lilanicus, Paecilomyces marquandii,
and Paecilomyces variotii are the ones included. Except for
strains of Paecilomyces lilanicus, the MICs of amphotericin B
tended to be very low while the MICs of flucytosine tended to be very high
except for strains of Paecilomyces variotii.
For all species
tested, fluconazole yielded considerably high MICs. Itraconazole and
ketoconazole MICs were lowest for Paecilomyces variotii compared to
other species. Voriconazole has been tested against Paecilomyces
lilanicus and Paecilomyces variotii and has yielded low MICs
for both of these species. Appeared active in vitro against
Paecilomyces were posaconazole, the novel triazole UR-9825, and
terbinafine. On the other hand, caspofungin lacks positive response
against Paecilomyces lilanicus but was active in vitro
against Paecilomyces variotii.
Amphotericin B and
flucytosine has been successfully used in treatment of some paecilomycosis
cases due to Paecilomyces lilanicus regardless of high MICs in
vitro. Additionally, caspofungin combined with itraconazole has also
been found to be effective in treating infection caused by Paecilomyces