Unit 4- Systemic Mycoses Flashcards
Infection
By inhalation but noncontagious
Dimorphism
Molds in saprophytic phases, coccidioides produces sporangia in tissue, others are budding yeasts
Lesions
Granulomatous in lung, systemic dissemination
Coccidiomycosis
Desert soil, primary lesions in lungs and secondary in bones, mostly dog, horse, cat, and human
Coccidioides Virulence
Adhesins in spherule outer wall glycoprotein, beta glucosidase 2 secreted by endospore, chitinase 1 releases endospores, beta-1 3-glucanosyltransferase gel, serine proteases, urease
Coccidioides Immune Response
IgM to Bgl2, TH1 to gel, and TH1 to urease
Coccidioides Growth
Simple media, mycelial on SAD or blood agar, gray colonies with aerial mycelium, arthroconidia produced after a few days
Coccidiomycosis Pathogenesis
Arthroconidia inhaled and form spherules, spherules release endospores that form new spherules, disseminates from lung to other tissues
Coccidiomycosis Diagnosis
Coccidioidin skin test, immunodiffusion, compliment fixation test, latex agglutination
Histoplasma capsulatum
Mycelium in saphrophytic phase with septate hyphae and spherical microconidia with tuberculate macroconidia with fingerlike projections, yeast in parasitic phase
Histoplasma Virulence
Histoplasmins from mycelium, adhesins to enter cells, calcium protein chelates calcium, H antigen elicits immune response in yeast phase, iron acquisition, M antigen catalase, melanin, phagolysosome acidification
Histoplasma Transmission
In soil and bird and bat droppings, inhalation of microconidia or hyphae
Histoplasmosis
Primary lesions in lungs and dissemination to other organs
Histoplasmosis Diagnosis
Histoplasmin skin test, immunodiffusion, compliment fixation, latex agglutination, immunofluorescence
Blastomyces dermatidis
Mold in saprophytic stage producing conidophores, budding yeast in tissue
Blastomyces Virulence
Bad1 adhesins prevent ROS and cytokines from phagocytic cells
Blastomycosis Pathogenesis
Spores inhaled to alveoli, acute pulmonary phase leads to self limiting control or asexual budding leading to pyogranulomatous inflammation in lungs or lymphatic and hematogenous spread of spores
Blastomycosis Diagnosis
SAD agar, intracellular yeast on examination
Aspergillus fumigatus
Molds with septate hyphae and characteristic asexual fruiting structures on conidophores
Conidiophores
Hyphal branches originating by a foot cell in mycelium and ending in a vesicle, vesicle covered in phialides that form chains of pigmented conidia
Aspergillus Virulence
Adhesins, PAMP cell wall triggers toll like receptors on macrophages, elastase, protease, phospholipase, iron acquisition, melanin
Aspergillus Growth
Grow on all common lab cultures, grow in environment, soil, vegetation, feed, air, and water
Aspergillosis Transmission
Inhalation or ingestion of environmental sources
Aspergillus fumigatus Pathogenesis
Inhalation or ingestion, opportunistic pathogen, suppurative exudate in pulmonary infection, mycelial growth into blood vessels, vasculitis, thrombus, systemic dissemination, granuloma in many tissues
Aspergillosis Epidemiology
Bovine abortion, coincides with poor husbandry in chickens, stress leads to outbreak, doliocephalic dogs get canine nasal aspergillosis, T-lymphocyte deficiency, antibacterials and steroids in horses predispose
Aspergillosus Immunity
Cell mediated immunity important, immune weakness leads to infection
Aspergillosis Diagnosis
Hyphae, fruiting heads, and conidia on direct examination, culture, immunodiffusion, ELISA, PCR
Pneumocystis carinii
Opportunistic pathogen causing pneumonia in immunocompromised horses and dogs
