Bacteriology - Mycoses 2 Flashcards
Dermatophyte infectious agents
Microsporum spp
Trichophyton spp
Dermatophytes features
Ringworm
Animals, birds, humans
Keritinized structures
Zoophilic
Geophysical
Anthropophilic
What effects Dermatophytosis pathogenesis?
Innate immunity, lack of trauma
Predisposing factors
Dermatophytosis clinical signs
Hair loss, scales, crusts, red skin (erythema), puritis (variable), papules/pustules/kerion
Dermatophytosis diagnosis (4)
Woods lamp
Cytology
Fungal culture
Histopathology
Woods lamp
40%, topical, scales
Not reliable
Wet mount cytology - derm
Superficial scraping, arthroconidia (in animal tissue)
When would you sample Dermatophytosis with a toothbrush?
Testing possible carrier animals not currently presenting with lesions
Dermatophytosis cultures
DTM - change to red
RSM - change to blue
3-7 days
Tape preparation results for macroconidia
M. Canis - common in dogs, cats as carriers
M. Gypseum - some dogs, less common
M. Nanum - pigs
Tape preparation findings for Trichophyton
T. Mentagrophytes - hyphae, common in agriculture
T. Verrucosum
What circumstances would warrant a histopath for Dermatophytosis?
Very severe infections
Cases that aren’t responding to current treatment
Sporothrix schenckii
Starts as cutaneous infection
Can become systemic
Sporotrichosis
Dimorphism fungus
Soil, roses, cats
Requires tissue damage
Cutaneous, lymphocutaneous, disseminated
What cytologic diagnosis is expected in sporotrichosis?
Macrophage filled with ovoid yeast
What species fall under Respiratory -> systematic infection?
Blastomyces
Histoplasma
Cryptococcus
Coccidioides
Etiology/morph of blastomyces
Enviro - fruiting body
Vito - broad based budding yeast
Etiology/morph of histoplasma
Enviro - fruiting bodies
Vito - tiny yeast, reliably found inside macrophages
Etiology/morph of cryptococcus
Narrow based budding yeast within capsule
-anti phagocytosis function
Etiology/morph of coccidioides
Enviro - hyphae
Vivo - endospore
BELLS in resp-systemic mycoses
Bones, brain
Eyes
Lymph
Lung
Skin
Bells - bones
Blastocyst, histoplasma & coccidiosis
Osteomyelitis, limping, arthritis, swelling
Bells - brain
CNS signs, depends on final destination of fungi
Ataxia, stumbling
Bells - eyes
Swelling, leakage, blindness
Bells - lymph
Lymphadomopathy, multi lymph swelling
Bells - lungs
Exercise intolerance, resp rate, panting
Diffuse lung damage, fungal circulation
Bells - skin
Severe patches, lesions, necrosis
Diagnosis of resp - systemic
Blood smear, cytology, histopath
Serum, urine, CSF
Avoid cultures
