Mycology (Fungus) - Lecture 4 Flashcards
Describe a fungal infection Eukaryotic or prokaryotic unicellular or multicellular Cell wall contents Reproducion
Eukaryotic, unicellular or multicellular
Multimorphic sturctures and stages
Cell wall contains chitin, ergosterol
Complex life cycles, sexual and asexual reproduction
What are four morphological stages of fungal infections?
1) Yeast or yeast-like stages
2) Pseudohyphae stages
3) Hyphae stages
4) Spores and spore-like stages
Describe the yeast or yeast-like stages
Sexual stages (conjugation) and asexual (budding) stages of reproduction Unicellulare, compromise mold
Describe pseudohyphae stages
Multicellular structures produced by incomplete budding
Describe hyphae stages
Multicellular structures, intricate connections and communication between cells
Long, filamentous, comprises mycelium
Describe spores and spore-like stages
Metabolically dormant, survive harsh environmental conditions, can travel through air
Unicellular structures
What are the four types of mycoses?
give examples of each
1) Superficial/cutaneous - Tinea
2) Subcutaneous - Sporothrichosis
3) Systemic - Blastomycosis, Histomycosis
4) Opportunistic - Candidiasis, Cryptococcosis, Pneumocystosis
Describe superficial/cutaneous mycoses
Fungal infection of the outermost layers of skin, hair and nails
Superficial - occur OUTSIDE the body
Cutaneous - occur IN the outer layers of the skin
Tinea = ringworm - infection due to fungus (NOT parasite)
Describe tinea capitis
What causes it?
Scalp ringworm
Fungal infection of the head and scalp - patches of hair loss, inflammation, itching, scaling, dandruf
Trichophyton and Microsporum cause it most commonly
Describe subcutatneous mycoses
Chronic, localized infection of the skin and tissue
may affect lymphatic system
May invade extradermal tissues
Describe sporotrichosis (Sporothrix schenkii)
Aka: Rose gardener’s disease
Affects the skin and lymph nodes
Causes nodular leasions at the point of entry and along lymphatic vessels
Can spread to joints, lung, bone
Describe systemic mycoses
Pass through the bloodstream
Primary systemic mycoses generally originate in the lung, and undergo hematogenous spread to other organs
What are systemic mycoses casused by?
Caused by dimorphic fungal pathogens - assume different morphologies at different body temperatures
- Mycelial at room temperature
- Yeast-like (spore) at body temperature
Give four examples of systemic fungal human pathogens
Blastomyces dermatiditis
Coccidioides immitis
Histoplasma capsulatum
Paracoccidioides brasiliensis
Who is more likely to get opportunistic mycoses?
Associated with immunosuppressed patients
- HIV-positive patients (AIDS-defining illness)
- Transplant recipients
- Elderly
- Premature babies