Contaminants/Opportunistic Fungi Clinical Microbiology Review 273
FUNGUS CLASSIFICATION SIGNIFICANCE COLONIAL MORPHOLOGY MICROSCOPIC MORPHOLOGY
Rhizopus
Mucor
Aspergillus
Hyphae: large, broad, nonseptate.
Produces horizontal stolons that at-
tach by rhizoids. Sporangiophores in
clusters opposite rhizoids. Terminate
in dark, round sporangia containing
sporangiospores.Like Rhizopus,but sporangiophores
may be branched. No rhizoids.Septate hyphae, branching at
45 °angle. Unbranched conidiophore
arises from foot cell. Expands into
large, spherical vesicle covered with
phialides that produce chains of
round conidia.Common laboratory con-
taminant. Propensity to
attack vascular system of
immunocompromised.
Rapidly spreading.
Often fatal.Common laboratory con-
taminant. Propensity to
attack vascular system of
immunocompromised.
Rapidly spreading.
Often fatal.Common contaminant.
Can cause invasive infec-
tion, colonization, toxico-
sis, allergy. A. fumigatus
is most common.ZygomycetesZygomycetesHyalineMature within 4 days. “Lid
lifter.” Front is dense cotton
candy–like growth, white at
first, turning gray or yellow-
ish brown. Reverse is white.Mature within 4 days. “Lid
lifter.” Front is dense cotton
candy–like growth, white at
first, turning gray. Reverse is
white.Mature within 3 days. Front is
fluffy, granular, or powdery
texture. White at first, then
color depends on species:
A. fumigatuswhite to blue-
green. A. nigerblack. A. flavus
yellow to green. A. terreustan
to cinnamon. Reverse is
white, goldish, or brown.continued...