Terms and Procedures Flashcards
BHI
Chloramphenical and cycloheximide (suppress fast growing saprophytes and bacteria)
Growth of Histoplasma capsulatum and Blastomyces dermatitidis
Mycosel Agar
Primary recovery of dermatophytes
Cornmeal Agar (CMA)
Identification of C. albicans
Niger Seed Agar (aka Bird Seed)
Identification of Cryptococcus neoformans
Potato Dextrose Agar (PDA)
Stimulate the sporulation of dermatophytes
Christensen’s Urea Agar
Used to differentiate between:
Cryptococcus species (negative) or Cryptococcus neoformans (positive)
T. mentagrophytes (positive) or T. rubrum (negative)
Trichosporon (positive)
Rapid Growers
< 7 days
Most saprophytes
Mucormycetes (Zygomycetes)
Coccidiodes immitus
Yeast
Moderate Growers
7-10 days
Dermatophytes (most)
Some saprophytes
Sporothrix schenkii
Slow Growers
> 10 days
Subcutaneous dematiaceous fungi (Phialophora, Cladophialophora, & Fonsecaea)
Dermatophytes (a few)
Systemic dimorphic fungi except Coccidiodes immitus
Topography
Flat (no topography)
Raised, folded, verrucose (wrinkled, convoluted, or wart-like)
Cerebriform (brain-like)
Rugose (deep furrows irregularly radiating from center)
Umbonate (button like central elevation)
Septate
Subdivided into individual cells by transverse walls or septa
Aseptate
Without transverse septa or walls
Aerial mycelium
Grows above the substrate and supports development of fruiting bodies
Vegetative mycelium
Extends downward into the nutrient substrate
Favic chandeliers
Terminal hyphal branches that are irregular, broad, and antler or moose-like appearance
Characteristic in Trichophyton schoenleinii
Spiral hyphae
Form coiled or cork-screw like turns
Commonly seen in Trichophyton species
Asexual Reproduction
Involves nuclear and cytoplasmic division in which 2 daughter cells contain same genetic information as one parent.
Seen most commonly in fungi
Poroconidia
Found in Bipolaris
Fruiting bodies are formed by daughter cell pushing through a minute pore in parent cell (conidiophore)
Annelloconidia
Found in Scopulariopsos
Arise from inside a vase-shaped structure called annellide
Blastospores/Blastoconidia
Budding forms produced by yeast
Cells are produced by budding when daughter cell is pinched off from portions of mother cell
Pseudohyphae
Elongated blastoconida that remain attached from structures called pseudohyphae
Chlamydospores/Chlamydoconia
Round, thick-walled resistant spores
Observed at the hyphal tip (chlamydospores), on the sides of hyphae (sessile chlamydospores), or within the hyphal strand (intercalary chlamydospores)
Arthrospores/Arthroconidia
Formed directly on hyphae by fragmentation through points of septation.
Mature they appear as square, rectangular, or barrel-shaped, thick-walled cells
Tease Mount
Small portion of colony including some of the subsurface is dug out with a pair of dissecting needles
Colony is teased apart with needles and overlaid with a cover slip
Scotch Tape Prep
Spore arrangement of more delicate molds are better preserved
Using frosted, clear cellophane tape, press sticky side gently but firmly to surface of the colony
Place a drop of LPCB
Stick end of tape to surface of slide
Slide Culture
Method used when tease mount of scotch tape prep cannot establish an accurate ID
Media is placed onto the glass slide
Organism inoculated on media
Cover slip placed on top and incubated
Hair Perforation Test
Obtain light colored hair from child and place into tube
Add 20-25 mL of sterile DI
Place several fragments of fungal culture into tube
Incubate and look for positive reaction
India Ink Prep
India Ink is placed on slide
Spinal Fluid or small amount of isolated yeast is added
Add cover slip
Look for capsulated yeast cells
Calcofluor White Stain
Binds to beta 1-3 and 1-4 polysaccharides
Fluoresces when exposed to UV radiation
Fungal elements stand out as bright apple green on a red background
Acid Fast Stain for Ascopores
Ascospores stain green
Vegetative cells stain red
Acid Fast Stain (Modified)
Nocardia species appear at least partially acid fast
KOH Prep
10% KOH is used to clear debris and dissolve keratinous material from skin, hair, and nails
Latex agglutination
Test for Cryptococcus neoformans in CSF
Wrights Giemsa Stain
Detect intracellular yeast forms of Histoplasma capsulatum in bone marrow
Mycotic
infection with fungus or disease caused by fungus
Keratitis
Inflammation of the cornea
Mycetomas
chronic, progressively destructive infectious disease of the subcutaneous tissues that spreads to affect the skin, deep tissues, and bone
Keratomycosis
invasive infection of corneal stroma
Onychomycosis
fungal infection of the nail unit
Phaeohyphomycosis
Rare mycotic infection caused by various heterogenous groups of phaeoid (dematiaceous) fungi involving the skin and subcutaneous tissue
