Mycology Flashcards
This agent causes Pityriasis Versicolor - hypo or hyper-pigmented macule on the skin
Malassezia furfur
How is Malassezia furfur ID’d?
spaghetti and meatballs appearance of organisms in skin scrapings
This agent causes Tinea Nigra - black macule on the skin
Exophiala werneckii
How is Exophiala werneckii ID’d?
Black 2 celled oval yeast in skin scrapings
This agent causes Black Piedra - black nodules on hair shaft
Piedraia hortai
What are the black nodules caused by Piedraia hortai composed of?
spore sacs and spores
This agent causes White Piedra - creme colored nodules on hair shaft
Trichosporum beigelii
What are the creme colored nodules caused by Trichosporum beigelii composed of?
hyphae that fragment into arthrospores
These three agents (dermatophytes) cause Tinea - ring worm
- Trichophyton
- Microsporum
- Epidermophyton
How are the dermatophytes that cause ring worm ID’d?
presence/absence and shape of micro and macro-conidia in scrapings from lesion
KOH mount of infected material with typical dermatophyte hyphae breaking up into arthoconidia
This agent causes Sporotrichosis (Rose Growler’s Disease) - nodules and ulcers along lymphatics at site of inoculation
Sporothrix schenckii
How is Sporothrix schenckii ID’d?
budding, cigar-shaped yeast in tissue exudate which converts to mold with rosette pattern of conidiation on culture at 25 degrees c
This agent causes Chromoblasomycosis - warty nodules which progress to Cauliflower-like nodules. Usually found on lower limbs.
Fonsecaea pedrosoi
How is Fonsecaea pedrosi ID’d?
copper colored spherical yeast called medlar bodies
This agent(s) causes Mycetoma (madurella foot) - draining sinus tracts at site of inoculation
Psudallescheria boydii
Madurella grisea
How is Pseudallescheria boydii/Madurella grisea ID’d?
white, brown, yellow or black granules in exudate that are fungal colonies
This agent(s) causes mycotic keratitis - raised corneal ulcers with occasional satellite lesions, plaques and pus in the anterior chamber of the eye
Fusarium solani
Candida albicans
Alternaria species
How is Fusarium solani ID’d?
crescent shaped macroconida
How is Candida albicans ID’d?
have pseudohyphae
How is Alternaria species ID’d?
unusual macroconida
This agent causes Histoplasmosis - 95% of cases: lung calcifications, 5% of cases: cough, chest pain, dyspnea, hoarseness, chronic progressive lung disease with calcifications
Histoplasma capsulatum
How is Histoplasma Capsulatum ID’d?
saprobic pahse - mold with tuberculate macroconidia at 25 C
parasitic phase - small yeasts in characteristic chains at 37 C
“Buckshot” picture on chest xray
True or false? Histoplasmosis is the most common systemic mycoses and is caused by inhalation of macroconidia from soil at bird and bat roosts along the major midwest river valleys
true
This agent causes North American blastomycosis - granulomatous and suppurative lesions of the lung (resembles TB) with eventual skin lesions
Blastomyces dermatitids
How is Blastomyces dermatitidis ID’d?
thick walled yeast with a broad base at 37 C
mold at 25 C
This agent causes South American blastomycosis and cutaneous blastomycosis
Paracoccidiodes brasilensis
Describe how South American blastomycosis and cutaneous blastomycosis present
South american blastomycosis: an initial lung disease with metastasis to skin and many organs
cutaneous blastomycosis: dry, crusted, sharply circumscribed lesions which resemble skin candidiasis
How is Paracoccidiodes brasilensis ID’d?
yeast with multiple buds at 37 C
yeast with septet hyphae at 25 C
This agent causes coccidiodomycosis - flu like symptoms to disseminated symptoms; 1% of pets have initial pneumonia followed by erythematous rash and ulcers and abscesses due to delayed hypersensitivity; fungus ball cavities in lung created by giant cell in a granuloma
Coccidodes immitis
How is C. immitis ID’d?
multinucleate spherule at 37 C
Septate hyphae with arthrospores at 25 C
Where is Coccidiodomycosis commonly seen?
southwest US and Mexico
This agent causes cryptococcosis - mild lung infection followed by meningitis and skin lesions
note: picked up near pigeon roosts and associated with CMI deficiency
cryptococcus neoformans
How is cryptococcus neoformans ID’d?
yeast with a large capsule at 25 C or 37 C
pink carminophillic capsules
This agent causes pneumocystic pneumonia - AIDS associated PCP interstitial pneumonia, also common infection in children
pneumocystis jiroveci
How is pneumocystis jiroveci ID’d?
microscopy of silver of Giemsa-stained sample of sputum, lavage, or lung tissue should show many CYSTS
How are the cysts associated with pneumocystic pneumonia produced?
sporozoites are released in the alveoli, attach to the epithelial cells, and initiate cycles of cyst formation and sporozoite release
This agent causes candidiasis (Thrush) - itching, white patches of cheesy creamy growth in the mouth, vagina, or esophagus, urethritis
Candida albicans
Candida glabrata
How is Candida ID’d?
yeast which produces germ tubes in serum
yeast produces pseudohyphae and chlamydospores when grown on corn meal agar in tissue
Aspergillus fumigatus cuases Aspergillosis. Describe how this disease presents.
fungus ball in paranasal sinuses, lung, or brain
note: disease occurs in IC/AIDS pts
How is Aspergillus fumigatus ID’d?
mold with septate; hyphae are at acute angles
This agent causes mucormycosis - fungus ball in eye, sinus, lung, skin, or brain
Rhizopus
Absidia Mucor
How are Rhizopus/Absidia Mucor ID’d?
hyphal forms at 25 C and 37 C
Mucormycosis is associated with what disease?
diabetes
