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53 Cards in this Set
- Front
- Back
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What is the primary predisposing factor for development of mucocutaneous candidiasis?
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T cell deficiency.
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What is the primary predisposing factor for development of systemic candidiasis?
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Neutropenia.
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Besides T cell deficiency and neutropenia, what other factors can predispose the patient for the development of candidiasis?
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Antibiotic use-due to effects on the normal flora. Pregnancy. Endocrine abnorm. Local tissue dmg. Malnutrition. Severe burns. Drug abuse. IV catheters
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What does Candida albicans look like in tissues?
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Budding yeast cells, hyphae and pseudohyphae.
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How can Candida albicans be differentiated from other Candida species in the laboratory?
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C. albicans makes germ tubes when incubated at 37*C in serum. C. albicans will make chlamydoconidia (chlamydospores) when grown on special media (corn meal or EMB agar).
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What treatment is used for superficial skin infections due to Candida infections?
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Nystatin
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What treatment is used for mucocutaneous Candida infection?
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Ketoconazole
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What treatment is used for treatment of systemic candidiasis?
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Amphotericin B
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What is the natural habitat of Candida albicans?
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Normal flora of the gut, vagina and oral cavity.
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What is the primary site of infection with Cryptococcus neoformans?
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The lungs.
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Upon dissemination systemically, C. neoformans has a predilection for what tissue?
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The central nervous system.
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What form of disease due to C. neoformans infection is most frequently diagnosed?
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Meningitis.
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What predisposes patients to development of infection with Cryptococcus neoformans?
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T cell deficiency. Especially important in the AIDS population.
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What does Cryptococcus neoformans look like in spinal fluid or other tissues?
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An encapsulated yeast cell. Capsule visualized in India ink preparations.
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What does Cryptococcus neoformans look like when grown in the laboratory at 30*C?
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An encapsulated yeast cell.
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What does Cryptococcus neoformans look like when grown in the laboratory at 37*C?
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An encapsulated yeast cell.
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What test is commonly done on serum or spinal fluid to detect infection with Cryptococcus neoformans?
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A test for the presence of cryptococcal antigen. Latex beads coated with antibody to cryptococcal antigen will agglutinate in the presence of serum or CSF that contains the antigen.
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What is the prognosis of non-compromised patients with localized pulmonary lesions due to C. neoformans?
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Good
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What is the prognosis for immunocompromised patients with systemic infection with C. neoformans?
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Very poor.
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What is the recommended treatment for cryptococcal meningitis?
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A combination of 5-FC and amphotericin B.
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After treatment of AIDS patients with cryptococcosis, they must be placed on maintenance therapy for life with what drug?
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Fluconazole.
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What is the natural habitat and endemic area for Cryptococcus neoformans?
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Found in the soil, especially in areas containing large amounts of pigeon feces. The organism is found worldwide.
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How is man infected with C. neoformans?
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Believed to be by inhalation of small, desiccated forms of the yeast found in the soil.
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What types of patients are at risk of developing pneumocystis pneumonia?
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Immunocompromised such as: AIDS, Bone marrow transplant, chronic corticosteroid treatment
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When do people become infected with Pneumocystis and how are they infected?
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By 4 years of age. Respiratory route.
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What immune response is primarily responsible for protection against pneumocystis pneumonia?
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CD4-mediated (or cell-mediated immunity)
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What two names may you see as the name for the etiologic agent of pneumocystis pneumonia?
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Pneumocystis jiroveci – new name. Pneumocystis carinii – old name
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What are the symptoms of pneumocystis pneumonia?
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Dry cough, fever, progressive dyspnea, rapid breathing. (only in immunocomp, normal individ do not develop this disease)
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What is used for prophylaxis of AIDS patients to prevent pneumocystis pneumonia?
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Pentamidine
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What range of infections can be caused by Aspergillus species?
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A wide spectrum from allergic to invasive infection.
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What is the most common species of Aspergillus that causes human infection?
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Aspergillus fumigatus.
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Aspergillus organisms are found throughout the world.
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TRUE, OH crap, we're all gonna die!!!!
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What type of hypersensitivity reaction can be induced after inhalation of Aspergillus conidia?
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Immediate hypersensitivity (IgE mediated).
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What clinical features are characteristic of allergic bronchopulmonary aspergillosis?
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Fungal growth in bronchi, asthma, immediate hypersens to aspergillus skin test, positive culture for aspergillus from sputum
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What clinical features are commonly associated with aspergilloma?
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Fungus ball in the lungs. Can be asymptomatic or result in productive cough and hemoptysis.
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What are the common sites of infection in noninvasive aspergillosis?
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Pulmonary cavitary, external ear canals, nasal cavity, eye, nail plate, paranasal sinuses
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What individuals are most susceptible to noninvasive aspergillosis?
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Immunosuppressed.
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What type of immunosuppression leads to invasive aspergillosis?
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Granulocytopenia (neutropenia).
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What can be a potential consequence of exposure to some of the metabolites of Aspergillus?
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They are toxic and carcinogenic.
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What does Aspergillus look like in tissues?
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Branching, septate hyphae.
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What does Aspergillus look like when grown in the laboratory?
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Mycelium bearing conidiophores on which are found phialides. Conidia are found at the tips of the phialides.
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Why is it difficult to prove that Aspergillus was cultured from a clinical specimen?
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This organism is a common contaminant in the air and therefore a contaminant of media used to grow fungi in the laboratory.
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What additional information helps establish that Aspergillus is the cause of an infection other than culture in the laboratory?
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Direct observation of septate hyphae in the clinical specimen.
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What other types of tests can be used to aid in the diagnosis of Aspergillosis?
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Detection of antigens by double diffusion or other immunologic assays.
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What is the treatment for aspergilloma?
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May range from none to surgical resection and treatment with antifungals (Amphotericin B and flucytosine).
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What is the treatment for invasive aspergillosis?
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Amphotericin B or itraconazole.
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What is the name for the disease caused by an opportunistic mycotic infection caused by a mold in the class Zygomycetes?
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Mucormycosis (also zygomycosis).
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What patient groups are susceptible to the development of mucormycosis?
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Ketoacidosis resulting from diabetes mellitus, drugs or uremia. Burn patients. Burn patients. Steroid therapy. Immunosuppressed.
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Several different fungal species can cause mucormycosis but two are quite prevalent. What are these two?
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Mucor, Rhizopus
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What types of infection can be caused in mucormycosis?
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Rhinocerbral infection. Thoracic infection causing destruction of lung parenchyma. Localized infection after tissue trauma. Kidney infection. Cutaneous infections
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What do the fungi that cause mucormycosis look like in tissues?
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Broad, irregular, branching, nonseptate hyphae. Key identifying feature: the branching, nonseptate hyphae.
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What do the organisms that cause mucormycosis look like when grown in the laboratory?
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Aseptate hyphae (also called coenocytic hyphae) with sporangiophores bearing sporangia which are filled with spores (sporangioconidia). If the species is Rhizopus, rhizoids will be seen. If it is Mucor, the rhizoids will not be present.
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What is the treatment for mucormycosis?
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Surgical debridement and Amphotericin B
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