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42 Cards in this Set
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T/F: candida are normal flora of ppl? Candida are uncommon nosocomial infections?
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T, F
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clinical manifiestations of candida?
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skin, nails, mucosal surfaces of mouth, vag, esophagus, bronchs; disseminated disease including heart and brain (very dangerous), associated with AIDs.
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diseases caused by candida?
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oropharyngeal infection, esophagitis, vulvovaginal infection, skin and nail infection, chronic mucocutaneous, UTI, pneumonia, endocarditis, pericarditis, CNS infection, ocular infection, bone and joint, abdominal infection, hematogenous infection
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what species of candida can cause infection? what are the risk factors associated with candidiasis?
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many species. surgery, valve disease, prosthetic valves, IV drugs, venous catheters, immunosuppression, ventricula shunts, tramau, intraarticular injections,diabetes, diabetic foot, pancreatitis, organ transplants, prolonged antibiotic use, ICU support, hemodialysis, age extremes, stem cell transplants, parenteral nutrition, denture wearers, chemotherapy, HIV, cancer, steroids, oral contraceptives, peripheral vascular disease, urinary catheter
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possible pathogenic mechanisms of candidia?
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bud-hyphae transmission, adherence, cell surface hydrophobicity, cell wall mannans, proteases and phosphipases, phenotypic switching
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diagnosis of candidia?
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yeast, pseudohyphae, septate hyphae in tissues. Culture positive specimens from normally sterile tissues, gram stain, need a lot of yeasts bc remember it is normal flora
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how can you speciate candida species?
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germ tube array plates and different species grow different color colonies
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treatment of candida?
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depends on severity and location: topical agents for cutaneous
systemic: amp B alone or in combo with 5 fluorocytosine. azole derivatives (oral availability) |
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describe the growth and morphology of aspergillus and give two important species.
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grows as mold with characteristic conidiophores. A fumigatus and A. flavus
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clinical manifestations of aspergillosis?
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allergic bronchopulminary disease, fungal colonization of pulmonary cavities, invasive disease involving many organs, often rapidly fatal
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pathogenesis of aspergillosis?
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cells secrete elestase, proteases, and catalse that may play a role in pathogenesis, gliotoxin inhibits phagocytosis and T cell activation, conidia bind to fibrinogen and laminin to set up resistance, neutrophils are important in clearing the infection
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diagnosis of aspergillosis?
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culture that produces septate hyphae that branch at regular intervals - good stain is methenamine silver
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treatment of aspergillosis?
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invasive disease requires aggressive therapy with amp B, or azoles (voriconazole is choice) can do capsofungin (chitin wall inhibitor as last resort)
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three agents that cause zygomycosis?
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rhizobium, absidia, mucro
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morphology of the zygomycosis orgs?
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coenocytic hyphae that are fragile and ribbon like with 90 degree branching that produces asuxually via sporangia. spores are infectious
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epi and mortality rate of zygomycosis?
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ubiquitous in the environment, fairly rare, but 70 to 100% fatal when infected
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clinical manifestations of zygomycosis?
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rhinocerebral: initiates in the paranasal sinuses that can invade into the brain in diabetics, can go to GI, lung, SQ, burn pts colonize and then becomes invasive esp in blood vessels
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diagnosis of zygomycosis.
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micro exam reveals hyphal filaments, silver stain, culture not reliable, will see vascular invasion and tissue necrosis
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treatment of zygomyosis?
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aggressive invasive treatment that is usually not very effective... AMP B and posacinazole (only azole that works)
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describe the classification and morphology of Pneumocystis carinii.
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classified with fungi but could be a parasite. trophic form is a uninucleated sporocyst or a mature spore case containing eight spherical spores
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clinical manifestations of pneumocystis carinii?
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AIDs pts and pneumonia: interstital pneumonitis with plasma cell infiltrates, death as a result of asphyxiation. subclinical infection in healthy ppl is frequent
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diagnosis of pneumocystis carinii?
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morphological ID of org in tissue stained with gomori methamine silver or giemsa
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treatment for pneumocystis carinii?
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TMP-SMX or pentamidine isethionate (note orgs can become resistant to treatment)
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opportunistic fungi?
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candida, aspergillus, mucormycosis AKA zygomycosis eg Rhizopus,
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infectious particle of candida?
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yeast and pseudohyphae
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tissue form of candida?
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yeast and paeudohyphae.
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2 common clinical presentations of candida?
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oral thrush and disseminated disease
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distinguishing morphology of candida?
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pseudohyphae have pinched off branch points
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T/F: zit like skin lesions, endopthalmitis, and abscesses of liver and spleen are seen in candidiasis?
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T
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negative aspects of AMP B? FCZ?
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nephrotoxic. hepatotoxic and interacts with many other drugs via P450
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infectious particle of aspergillus? tissue form?
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conidia (spores). narrow septate hyphae with acute angle branching (dichotomous)
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specefic risk factors for aspergillus?
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abnormal mucociliary clearance, macrophage phagocytosis defects (as well as neutropenics and CGD - oxidase mechanisms do not work)
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what are the main risk factors for mucormycosis/zygomycosis?
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neutropenics and poorly controlled diabetics
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infectious particles of cryptoccus.
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probably dessicated yeast
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tissue form of cryptocccus?
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encapsulated narrow based budding yeast
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clinical manifestations of cryptococcus?
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pulmonary crypto, chronic meningitis
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what immunocompromised group is NOT at risk for getting cryptococcus infections?
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neutropenics
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diagnosis of cryptococcus?
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india ink smear of CSF, serum crypto antigen, culture CSF, blood, urine, sputum.
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treatment for crypto?
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AMP B, FCZ
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properties of histoplasma?
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infectious particle is microconidia, tissue form is tiny intracellular budding yeast in mononuclear phags. can be pulmonary or disseminated... usually in AIDs with fever and destructive GI lesion. Dx smear, culture, urine, histo antigen, hist complement fixation test. complement fixation. Tx: itraconazole, for dissemenated do lipid formulations of amph B
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describe Blastomyces.
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infectious particle is conidia, tissue form is broad based budding, pulmonary or disseminated, smear and stain Dx, Tx: itraconazole, AMP B
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describe coccidioides?
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barrel shapped arthroconidia are infectious, tissue form are spherules and tiny endospores, presentation are pulmonary disease, meningitis, disseminated disease, skin infections, Tx is FCZ, ampho B
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