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50 Cards in this Set
- Front
- Back
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List the Pathogenic Fungi that act as Cutaneous infective agents.
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- Epidermophyton species
- Microsporum species - Trichophyton species |
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List the Pathogenic Fungi that act as Subcutaneous infective agents
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- Actinomadura madurae
- Cladosporium - Madurella grisea - Phialophora - Sporothrix schenckii |
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List the Pathogenic Fungi that act as Stemic infective agents
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- Blastomyces dermatitidis
- Coccidioides immitis - Histoplasma capsulatum - Paracoccidioides brasiliensis |
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List the Fungi that act as Opportunistic pathogens
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Absidia corymbifera Aspergillus fumigatus Candida albicans Cryptococcus neoformans Pneumocystis jiroveci Rhizomucor pusillus Rhizopus oryzae (aka R. arrhizus) |
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Cell membrane of fungi
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Composed of ergosterols synthesis of ergosterol target of many antifungal agents |
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Fungal cell wall
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- Comosed of chitin
- polymer of N-acetylglucosamine, mannose, and glucose polysaccharide polymers |
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List the pathogenic dimorphic fungi
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- Sporothrix schenckii
- Coccidioides immitis - Histoplasma capsulatum - Blastmyces dermatitidis - Paracoccidioides brasiliensis |
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Geographic distribributation of Sporotrichosis
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- Common in the US, unlike most subcutaneous mycoses
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Characterization of typical Sporotrichosis infection
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- Granulomatous lesions/ulcers at the puncture site
- secondary lesions run along draining lymphatics. - displays yeast form in infected tissue, mycelial form when cultured - self-limiting or chronic |
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Causitive organism of sporotrichosis
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- Sporothrix schenckii
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Chromomycosis
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- warty nodules spread along lymphatics
- crusty abcesses |
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Treatment of Chromomycosis
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- treated with surgery and antifungals
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Geographical Distribution of chromomycosis
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- tropical and subtropical regions
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Mycetoma
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- localized abscesses usually on feet
- abscesses discharge pus, serum and blood through sinuses (abnormal channels) - can spread to bone crippling deformities |
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Causitive organisms of Mycetoma
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- various soil fungi
- Madurella grisea - Actinomadura madurae - actinomycetes |
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Defining characteristic of Mycetoma
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- presence of colored grains
- color is characterist of the causative organism (black, white, red, yellow) |
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Treatment for Mycetoma
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- surgical excision
- no effective chemotherapy. |
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Systemic mycoses caused by true pathogens (infect healthy people)
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- Coccidioidomycosis
- Histoplasmosis - Blastomycosis - Paracoccidiomycosis |
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Systemic Mycoses caused by opportunistic pathogens (debilitated are infected)
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- Candidiasis
- Cryptococcosis - Aspergillosis - Mucormycocis - Pneumocystis jiroveci |
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Geographic ditribution of Coccidioidomycosis
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- arid areas of southwestern United States
- Central and South America |
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Pathology of Dimorphic fungi
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- inhalation of airborne spores common in endemic areas
- asymptomatic primary pulmonary infection common - acute pulmonary disease less common - chronic pulmonary/disseminated infection rare |
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Means of infection by Coccidioides immitis
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- Fungus grows in soil
- generates spores by septaton of hyphal filaments, aka arthrospores. - airborne sproes are inhailed and germinate in lunges |
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Dissemination of Coccidioidomycosis
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- from lungs to CNS and bone.
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Pathology of Coccidioidomycosis in the lung
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- germinating spores develop into large spherules (20-40 micrometers)
- spherules filled with endospores - rupture of spherule releases endospores - each endospore can form a new spherule |
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Diagonis of coccidioidomycosis
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- culture (dangerous to work with, risk of lab infections)
- histopathology - serology |
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Geographical distribution of Histoplasmosis
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- worldwide
- most prevalent in central North America -Ohio and Mississippi River valleys |
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Mechanism for Histoplasmosis infection
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- found in high nitrogen soil (bat and bird dropping rich)
- germinate conidia that become airborn and are inhaled. - germinate in lungs into yeast-like cells |
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Pathology of Histoplasmosis
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- Yeast cells in lungs are engulfed by macrophages
- fungus multiplies in macrophages - only fungus to exhibit intracellular parasitism |
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Dissemination of Histoplasmosis
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- invasion of reticuloendothelial system.
- liver - spleen - lymph nodes - Bone marrow - skin - CNS - adrenals |
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Histoplasmosis diagnosis
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- Culture
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Mechanism of blastomycosis infection
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- fungus produces microconidia in soil which become airborne.
- germinate into thick walled yeast cells |
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Pathology of Blastomycosis
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- germinates into thick walled yeast cells
- can disseminate to - skin (70%) - bone (30%) - genitourinary tract (20%) - manifests as ulcerated granulomas |
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Geographic distribution of Blastomycosis
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- Southeastern and south central US
- Great lakes - Ohio and Mississippi river valleys |
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Diagnosis of Blastomycosis
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- Culture of sputum, BAL, lung biopsy, other tissue
- no sensistive or specific serology or antigen test |
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Geographic distribution of Paracoccidioidomycosis
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South America Latin America
-major endemic dimorphic fungus in Latin America |
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Pathology of Paracoccidioidomycosis
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-similar to histoplasmosis and blastomycosis
- except most common secondary site of infection of mucosa of mouth and nose - destructive lesions develop - 90% of disease is in males - female hormones possibily inhibitory |
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Paracoccicioidomycosis diagnosis
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- Mariner's wheel morphology in culture
- sputum, BAL, tissues, scrapings - serologic testing |
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Diagnosis of Candidiasis
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culture
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Cryptococcocis Pathology
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- mild lung infection
- immunocompromised - disseminates to brain and meninges - %50 of cryptococcal meningitis have no immunologic defect |
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Cryptococcocis distribution
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- worldwide
- found in soil containing bird droppings, esp pigeon |
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diagnosis of cryptococcocis
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- thick capsule visible by India ink
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Pathology of aspergillosis
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- superficial:
otomycosis onchomycosis keratitis (could lose cornea) - invasive pulmonary, angioinvasion of endothelium leades to hemoptysis - disseminated progressive pulmonary contiguous spread or hematogenously |
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Allergic diseases manifestations of aspergillosis
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- aberrant host immune response to Aspergillus high IgE
-eosinophilia leads to pulmonary figrosis - occurs in immunocompentent patients - chronic sinusitis, nasal obstruction, headache, nasal polyps - hypersensitivity pneumonitis |
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Allergic bronchopulmonary aspergillosis
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- long-term allergic response to aspergillus
- immune response to aspergillus hyphae colonizing airways - may progress to bronchiectasis, permanent lung damage |
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Pathology of aspergillosis
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- mass of hyphae growing in previously existing pulmonary cavity or in a sinus cavity
- surgical removal if possible - asymptomatic or progressive to death |
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Diagnosis of Aspergillus
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- direct examination of tissues, BAL
look for granulomas in tissue radiating chains of septate hyphae with dichotomous branching (45 degrees) - culture - Aspergillus galactomannan antigen in serum |
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Mucorymcosis cause
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- zygomycetes group of filamentous fungi
-non-septate fungi - rhizopus most common genus - ubiquitous in nature |
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Pathology of Mucormycosis
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- affects immunocompromised, diabetes, burns, etc.
- begins in nasal mucosa or sinuses - progresses to orbits, palate and brain - very aggressive, rapidly fatal |
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Pneumocystis jiroveci
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- causes pneumonia in immunosuppressed, esp. HIV patients
- ubiquitous in nature - possible latent infection - hallmark is hypoxemia |
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Diagnosis of pneumocystis jiroveci
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- direct microscopy
- cannot be cultured in vitro |
