Medical Mycology Flashcards
What are the two structural types of fungi?
Yeasts - unicellular
Molds - filamentous, multicellular
What are hyphae?
Branching structures of molds which are either coenocytes or septate
Can be vegetative, reproductive, or aerial
What is the characteristic pathogenic factor of Candida albicans?
Adhesins
What is the characteristic pathogenic factor of C. neoformans?
Antiphagocytic capsule
What is the characteristic pathogenic factor of H. capsulatum?
Ability to survive in macrophage
How do most mycotic infections occur?
Lack of host resistance rather than destructive or invasive factors in the fungal pathogen
How are fungal infections classified?
According to the tissues that are initially colonized by them
E.g. superficial, cutaneous, systemic
What is a KOH mount?
Solution of KOH allows fungi to be observed under light microscope with or without staining
What is a Calciflor white stain?
Rapid, detects fungal cell wall chitin by bright fluorescence
Used for all fungi
What is a Periodic acid - Schiff reagent stain?
Histologic stain for fungi
Periodic acid forms aldehyde from chitin, Schiff reagent reacts with aldehyde to form redy dye
Stains both yeasts and hyphae
What is a Gomori Methenamine Silver Stain?
Detects fungi in histologic sections and Pneumocystis jirovecii cysts in respiratory specimens
Best stain for detecting all fungi
How do most fungi appear on a gram stain?
Gram positive
However, some appear gram-negative (C. neoformans)
What is a Giemsa stain?
Detects intracellular Histoplasma capsulatum and both intracystic and trophic forms of Pneumocystis jirovecii
Can stain other organisms
What is the most commonly used agar for culturing of fungi?
Sabouraud’s Agar
