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Unformatted text preview: MYCOLOGY Fungal diseases may be discussed in a variety
of ways. The most practical method for medical
students is the clinical taxonomy which divides
the fungi into:
Opportunistic mycoses Principal tissue sites of deep mycoses in comparison to those of the superficial, cutaneous, and subcutaneous mycoses. SUPERFICIAL MYCOSES The superficial (cutaneous) mycoses are usually
confined to the outer layers of skin, hair, and nails,
and do not invade living tissues. The fungi are called
dermatophytes. Dermatophytes, or more properly,
keratinophilic fungi, produce extracellular enzymes
(keratinases) which are capable of hydrolyzing
keratin.There are three genera of dermatophytes:
Malassezia furfur 秕秕秕秕秕秕
Trichophyton species (19 species) 秕秕秕
Microsporum species 秕秕秕秕秕
Epidermophyton floccosum. 秕秕秕秕 Malassezia furfur 秕秕秕秕秕秕
Malassezia furfur is a lipophilic “yeast” found
on skin flora. It can cause the following
disorders: Pityriasis versicolor Fungemia in premature infant Trichophyton species 秕秕秕
species These infect skin, hair and nails. Rarely can cause
subcutaneous infections, in immunocompromised
individuals. Take 2-3 weeks to grow in culture. The
conidia are large (macroconidia), smooth, thin-wall,
septate (0-10 septa), and pencil-shaped; colonies a re
a loose aerial mycelium which grow in a variety of
colors. Identification requires special biochemical and
morphological techniques (figure 10). Trichophyton
rubrum is presently the most common cause of tinea
in South Carolina. in Microsporum species ( 秕秕秕秕秕 )
Microsporum These may infect skin and hair, rarely nails. Its
prevalence has decreased significantly. When
prevalent (15-20 years ago), this organism could be
easily identified on the scalp because infected hairs
fluoresce a bright green color when illuminated with a
UV-emitting Wood's light. The loose, cottony mycelia
produce macroconidia (figure 11) which are thickproduce
walled, spindle-shaped, multicellular, and echinulate
(spiny). Microsporum canis is one of the most
common dermatophyte species infecting humans. common Epidermophyton floccosum 秕秕秕秕 .
Epidermophyton These infect skin and nails and rarely hair. They form
yellow-colored, cottony cultures and are usually
readily identified by the thick, bifurcated hyphae with
multiple smooth, club-shaped macroconidia. multiple Fungi of subcutaneous infection Chromomycosis (caused by several
species of black molds; Fonsecaea
edrosoi, Cladosporium carrionii,
Phialophora verrua have been isolated
most Sporothrix schenckii
秕秕秕秕秕秕 SPOROTRICHOSIS is Primarily a disease of the cutaneous tissue and lymph nodes. Recently, pulmonary disease.
SPOROTRICHOSIS Systemic mycoses
Systemic Cryptococcus neoformans
厌厌厌厌厌厌厌厌 Portals of entry of pathogenic and opportunistic fungi causing deep mycoses. Cryptococcus neoformans Oval , budding yeast surrounded by a wide polysaccharide capsule Cryptococcus neoformans
Cryptococcus Cryptococcus neoformans
No human to human transmission
Infection follows inhalation of the cell of C. neoformans, which , in nature , are thought to be small , allowing the organism to enter deep into the lung. Histoplasmosis
Histoplasmosis An intracellular mycoses of the reticuloendothelial system, attacking lungs, liver, spleen, bone marrow and occasionally kidneys, adrenals and intestines. COCCIDIOIDOMYCOSIS It may occur as either an acute, benign, selflimited disease or a chronic, malignant disseminated disease involving the cutaneous, subcutaneous, visceral or osseous tissue. Opportunistic Mycoses
Opportunistic Candida 厌厌厌厌厌厌厌
Pneumocystis carinii( 厌厌厌厌厌厌
厌厌厌厌厌厌 Candida albicans
Candida Aspergillus fumigatus; Aspergillus niger; Aspergillus
Aspergillus flavus Allergic - hypersensitivity to the organism.
Aggressive tissue invasion. Primarily a pulmonary
disease, but the aspergilli may disseminate to any organ.
They may cause endocarditis, osteomyelitis, otomycosis
and cutaneous lesions.
Fungus ball which is characteristically seen in the old
cavities of TB patients. This is easily recognized by x-ray,
because the lesion (actually a colony of mold growing in
the cavity) is shaped like a half-moon (semi-lunar growth).
The patients may cough up the fungus elements because
the organism frequently invades the bronchus. Chains of
conidia can sometimes be seen in the sputum.
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This note was uploaded on 12/27/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.
- Fall '11