MYCOLOGY
MYCOLOGY
Fungal diseases may be discussed in a variety
Fungal diseases may be discussed in a variety
of ways. The most practical method for medical
of ways. The most practical method for medical
students is the clinical taxonomy which divides
students is the clinical taxonomy which divides
the fungi into:
the fungi into:
Superficial mycoses
Superficial mycoses
Subcutaneous mycoses
Subcutaneous mycoses
Systemic mycoses
Systemic mycoses
SUPERFICIAL MYCOSES
SUPERFICIAL MYCOSES
The superficial (cutaneous) mycoses are usually confined to The superficial (cutaneous) mycoses are usually confined to the outer layers of skin, hair, and nails, and do not invade
the outer layers of skin, hair, and nails, and do not invade
living tissues. The fungi are called dermatophytes.
living tissues. The fungi are called dermatophytes.
Dermatophytes, or more properly, keratinophilic fungi, produce
Dermatophytes, or more properly, keratinophilic fungi, produce
extracellular enzymes (keratinases) which are capable of
extracellular enzymes (keratinases) which are capable of
hydrolyzing keratin.There are three genera of dermatophytes:
hydrolyzing keratin.There are three genera of dermatophytes:
Malassezia furfurMalassezia furfur 秕糠马拉癣菌秕糠马拉癣菌
Trichophyton Trichophyton species (19 species)species (19 species) 毛癣菌毛癣菌 MicrosporumMicrosporum species species 小孢子癣菌小孢子癣菌
Malassezia furfur
Malassezia furfur
秕糠马拉癣菌
秕糠马拉癣菌
Malassezia furfur is a lipophilic “yeast” found
Malassezia furfur is a lipophilic “yeast” found
on skin flora. It can cause the following
on skin flora. It can cause the following
disorders:
disorders:
Pityriasis versicolor
Pityriasis versicolor
Trichophyton
Trichophyton
species
species
毛癣菌
毛癣菌
These infect skin, hair and nails. Rarely can cause These infect skin, hair and nails. Rarely can cause subcutaneous infections, in immunocompromised
subcutaneous infections, in immunocompromised
individuals. Take 2-3 weeks to grow in culture. The
individuals. Take 2-3 weeks to grow in culture. The
conidia are large (macroconidia), smooth, thin-wall,
conidia are large (macroconidia), smooth, thin-wall,
septate (0-10 septa), and pencil-shaped; colonies a re
septate (0-10 septa), and pencil-shaped; colonies a re
a loose aerial mycelium which grow in a variety of
a loose aerial mycelium which grow in a variety of
colors. Identification requires special biochemical and
colors. Identification requires special biochemical and
morphological techniques (figure 10). Trichophyton
morphological techniques (figure 10). Trichophyton
rubrum is presently the most common cause of tinea
rubrum is presently the most common cause of tinea
in South Carolina.
Microsporum
Microsporum
species (
species (
小孢子癣菌
小孢子癣菌
)
)
These may infect skin and hair, rarely nails. Its These may infect skin and hair, rarely nails. Its prevalence has decreased significantly. When
prevalence has decreased significantly. When
prevalent (15-20 years ago), this organism could be
prevalent (15-20 years ago), this organism could be
easily identified on the scalp because infected hairs
easily identified on the scalp because infected hairs
fluoresce a bright green color when illuminated with a
fluoresce a bright green color when illuminated with a
UV-emitting Wood's light. The loose, cottony mycelia
UV-emitting Wood's light. The loose, cottony mycelia
produce macroconidia (figure 11) which are
produce macroconidia (figure 11) which are
thick-walled, spindle-shaped, multicellular, and echinulate
walled, spindle-shaped, multicellular, and echinulate
(spiny). Microsporum canis is one of the most
(spiny). Microsporum canis is one of the most
common dermatophyte species infecting humans.
Epidermophyton floccosum
Epidermophyton floccosum
表皮癣菌
表皮癣菌
.
.
These infect skin and nails and rarely hair. They form These infect skin and nails and rarely hair. They form
yellow-colored, cottony cultures and are usually
yellow-colored, cottony cultures and are usually
readily identified by the thick, bifurcated hyphae with
readily identified by the thick, bifurcated hyphae with
multiple smooth, club-shaped macroconidia.
Fungi of subcutaneous
Fungi of subcutaneous
infection
infection
Chromomycosis (caused by
Chromomycosis (caused by
several species of black
several species of black
molds; Fonsecaea edrosoi,
molds; Fonsecaea edrosoi,
Cladosporium carrionii,
Cladosporium carrionii,
Phialophora verrua have been
Phialophora verrua have been
Sporothrix schenckii
Sporothrix schenckii
申克孢子丝菌
申克孢子丝菌
SPOROTRICHOSIS is Primarily a
SPOROTRICHOSIS is Primarily a
disease of the cutaneous tissue
disease of the cutaneous tissue
and lymph nodes. Recently,
and lymph nodes. Recently,
pulmonary disease.
pulmonary disease.
Systemic mycoses
Systemic mycoses
Cryptococcus neoformans
Cryptococcus neoformans
Histoplasma capsulatum
Histoplasma capsulatum
Coccidioides immites
Coccidioides immites
(
(
厌酷球孢子菌〕
厌酷球孢子菌〕
Blastomyes dermatitides
Blastomyes dermatitides
（
（
皮炎芽生菌〕
皮炎芽生菌〕
Paracoccidiodes brasiliensis
Paracoccidiodes brasiliensis
Portals of entry of pathogenic and
Cryptococcus neoformans
Cryptococcus neoformans
Oval , budding yeast
Oval , budding yeast
surrounded by a wide
surrounded by a wide
Cryptococcus neoformans
Cryptococcus neoformans
Cryptococcus neoformans
cryptococcosiscryptococcosis
No human to human transmissionNo human to human transmission Infection follows inhalation of the Infection follows inhalation of the
cell of C. neoformans, which , in cell of C. neoformans, which , in
nature , are thought to be small , nature , are thought to be small ,
allowing the organism to enter allowing the organism to enter
Histoplasmosis
Histoplasmosis
An
An
intracellular
intracellular
mycoses of the
mycoses of the
reticuloendothelial system,
reticuloendothelial system,
attacking lungs, liver, spleen,
attacking lungs, liver, spleen,
bone marrow and occasionally
bone marrow and occasionally
COCCIDIOIDOMYCOSIS
It may occur as either an acute,
It may occur as either an acute,
benign, self-limited disease or a
benign, self-limited disease or a
chronic, malignant disseminated
chronic, malignant disseminated
disease involving the cutaneous,
disease involving the cutaneous,
subcutaneous, visceral or osseous
subcutaneous, visceral or osseous
Opportunistic Mycoses
Opportunistic Mycoses
Candida
Candida
（
（
假丝酵母菌）
假丝酵母菌）
Aspergillus
Aspergillus
（
（
曲霉）
曲霉）
Mucor
Mucor
（
（
毛霉）
毛霉）
Pneumocystis carinii(
Pneumocystis carinii(
卡氏肺孢
卡氏肺孢
菌）
Candida albicans
Aspergillus fumigatus
Aspergillus fumigatus
;
;
Aspergillus niger
Aspergillus niger
;
;
Aspergillus flavus
Aspergillus flavus
Allergic - hypersensitivity to the organism. Allergic - hypersensitivity to the organism.
Aggressive tissue invasion. Primarily a pulmonary disease, Aggressive tissue invasion. Primarily a pulmonary disease,
but the aspergilli may disseminate to any organ. They may
but the aspergilli may disseminate to any organ. They may
cause endocarditis, osteomyelitis, otomycosis and cutaneous
cause endocarditis, osteomyelitis, otomycosis and cutaneous
lesions.
lesions.
Fungus ball which is characteristically seen in the old cavities Fungus ball which is characteristically seen in the old cavities
of TB patients. This is easily recognized by x-ray, because the
of TB patients. This is easily recognized by x-ray, because the
lesion (actually a colony of mold growing in the cavity) is
lesion (actually a colony of mold growing in the cavity) is
shaped like a half-moon (semi-lunar growth). The patients
shaped like a half-moon (semi-lunar growth). The patients
may cough up the fungus elements because the organism
may cough up the fungus elements because the organism
frequently invades the bronchus. Chains of conidia can
frequently invades the bronchus. Chains of conidia can
sometimes be seen in the sputum.
