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50 Cards in this Set
- Front
- Back
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what are the etiological agents that cause Systemic Mycoses?
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1. Blastomyces dermatitidis
2. Coccidioides immitis & posadasii 3. Histoplasma capsulatum (var capsulatum & var duboisii) 4. Paracoccidioides brasiliensis 5. Penicillium marneffei |
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what disease does Blastomyces dermatitidis cause?
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Blastomycosis
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A patient has been working in the Eastern United States (river basin states) and comes into the office with what appears to be bacterial pneumonia, he has a high fever, lobar infiltrates, and is have signs of RDS. How do you determine if it is a bacteria or a fungus that is causing the problem? what is the fungus?
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1. Microscopic morphology: a typical yeast forms in tissue, sputum, or lavage material
2. Confirm with doing a culture of the sputum at 25 C and 37 C to observe morpholigical conversion 3. The fungus would be Blastomyces dermatitidis |
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how is an infection of Blastomycosis transmitted by Blastomyces dermatitidis?
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Blastomyces dermatidis lives in decaying organic material.
Inhalation of aerosolized conidia by both genders. |
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who are particularly susceptible to an infection of Blastomyces dermatitidis?
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Canines
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Is Blastomycosis contagious?
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NO
Blastomycosis is caused by a fungus, Blastomyces dermatidis, and transmitted when the conidia are inhaled |
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what are the virulence factors of Blastomyces dermatitidis?
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Thermally dimorphic
@ 25 C grows as mold with conidia produced terminally on short hyphal branches with chlamydospores @ 37 C a parasitic yeast with multiple nuclei and thick walls Reproduces by bud or blastoconidia |
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How does Blastomyces dermatitids causing Blastomycosis clinically manifest itself?
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1. Asymptomatic or flu-like symptoms
2. Severe cases: resembles bacterial pneumonia with RDS, high fever, lobar infiltrates, & respiratory failure 3. Chronic form: mass lesions or fibronodular infiltrates, extrapulmonary dissemination involves skin and bones 4. Chronic cutaneous resembles squamous cell carcinoma |
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How does Blastomycoses dermatitidis appear under the microscope?
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observation of typical yeast form in tissues, sputum, or lavage material
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How do you confirm a Blastomycoses dermatitidis infection?
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Should confirm by culture at 25 C and 37 C to observe morphological conversion
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How would you treat a patient after you diagnosed them with Blastomycosis dermatidis infection of Blastomycosis?
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Amphotericin B for most serious form
Itraconazole or Fluconazole |
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What causes Coccidioidomycosis?
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Coccidioides immitis and posadasii
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who are Coccidioidomycosis infections the most prominent in?
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elderly and immunocompromised
healthy individuals will by asymptomatic |
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A patient who lives and works outside in the Southwest US and sometimes travels to Mexico comes to your office complaining of allergies and flu-like symptoms. What do you suspect could be causing this?
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Coccidioides immitis & posadasii in healthy individual would most likely present this way.
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If you had a patient that was immunocompromised, recently traveled to SW US and was in an area where it was dusty, when they come to your office they complain that they had some flu-like symptoms that have progressively gotten worse. What is something you could suspect?
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Coccidioidomycosis
this is caused by coccidioides immitis and posadasii affects immunocompromised patients and elderly |
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what are the virulence factors of a Coccidioidomycosis infection caused by Coccidioides immitis/posadasii?
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1. Mold: vegetative and fertile hyphae, both fragmenting into arthroconidia
2. Accesses pulmonary tissue by inhalation where it converts to large spherules with numberous endospores, which form progeny spherules 3. This is extremely virulent (<10 arthrospores for infection) |
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what is a culture of Coccidioides immitis/posadasii not recommended?
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because of the virulence
takes less than 10 arthrospores to cause infection |
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what is used in place of culturing the Coccidioides immitis/posadasii responsible for causing Coccidioidomycosis?
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Antigenic reactions
Nucleic acid probes Serological test |
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How would you treat a patient with Coccidioidomycosis?
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initial Amphotericin B followed by prophylactic azole therapy for extended periods
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what is the etiological agent for histoplasmosis?
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Histoplasma capsulatum (var capsulatum & var duboisii)
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where are Histoplasma capsulatum found in nature?
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Soil with high nitrogen content
-growth potentiated by large amounts of bird or bat waste |
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There are two different species of Histoplasma where are each one of them found?
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Histoplasma capsulatum: eastern US
Histoplasma duboisii: tropical Africa |
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How is a Histoplamosis infection transmitted?
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inhalation of aerosolized hyphal fragments and conidia when the soil is disturbed
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Are the Histoplamsma capsulatm thermally dimorphic?
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YES
25 C: Hyaline MOLD, with micro and macroconidia 37 C: YEAST, difference in size and wall thickness between varieties |
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What type of infection does Histoplasma var casulatum cause?
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asymptomatic infection, with possible self-limiting acute pulmonary disease
Rare RDS and mediastinal fibrosis |
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If a Histoplasma infection disseminates what happens?
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Dissemination of a Histoplasma capsulatum infection results in chronic, acute/subcutaneous disseminated histoplasmosis
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when examining Histoplasma species under the microscope what is observed?
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YEAST phase
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How would the lab confirm diagnosis of Histoplasma capsulatum causing Histoplasmosis?
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confirmation by thermally dimorphic conversion
antigenic assay Nucleic acid probe |
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what is used to diagnose a disseminated infection of Histoplasmosis?
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Enzyme immunosassay
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You have decided your patient has Histoplasmosis because yeast were observed under the microscope, thermal dimorphism was observed in culture of 25 C hyaline mold and 37 C Yeast. They have signs of acute pulmonary disease. How do you treat it?
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Amphotericin B followed by Itraconazole orally, long term
This treatment would usually only be fore a histoplasmosis infection that has disseminated otherwise it would not be indicated because Histoplamosis infections are self limiting |
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What fungi causes Paracoccidiodomycosis?
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Paracoccidioides brasiliensis.
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Where is Paracoccidioides brasillensis found in nature?
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SOIL
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What is the disease that is known as South American Blastomycosis caused by?
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Paracoccidioides brasiliensis
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How is Paracoccidioidomycosis transmitted?
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inhalation or percutaneous inoculation
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who is Paracoccidioidomycosis most prevalent in?
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Most common in MEN
(90% of cases) |
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Is a Paracoccidioidomycosis infection contagious?
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NO
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Describe the Virulence factors of Paracoccidioidomycosis infection.
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Paracoccidioides brasiliensis causes the infection
Thermally Dimorphic 1. @25 C Hyaline MOLD with septate hyphae and chlamydoconidia (not helpful to ID) 2. @37 C: YEAST variable size with double refractile walls and single to multiple blastonconidia connected to parent through narrow necks |
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Describe the clinical manifestation of Paracoccidioidomycosis.
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Chronic pulmonary infection with respiratory symptoms, including pulmonary lesions.
Infection can disseminate in absence of therapy |
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What is seen in infected tissue and fluid of a Paracoccidioidomycosis infection?
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Characteristic YEAST form in infected tissue or fluids
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How is a diagnosis of Paracoccidioidomycosis confirmed?
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thermal dimorphism in culture
Antigen test Serological test |
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how do you treat a patient with Paracoccidioidomycosis?
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Itraconazole
Amphotericin B for more serious infections |
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What disease does Penicillium marneffei cause?
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Penicilliosis marneffei
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who is Penicilliosis marneffei infections found in?
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AIDS patients in Southeast Asia and China
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what is the source of Penicillium marneffei?
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bamboo rats and soil
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how is Penicilliosis marneffei transmitted?
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inhalation of conidia
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Virulence Factors:
25 C: MOLD with soluble RED pigment 37 C: pathogenic yeast phase: divides by fission and possesses a transverse septum What etiologic agent is this? what disease does it cause? |
Penicillium marneffei
Penicilliosis marneffei |
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What would a patient with a Penicilliosis marneffei infection present as?
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Primary: disseminated infection to many tissues and organs
Skin lesions on trunk and face |
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When looking at a Penicillium marneffei specimen under a microscope what is observed?
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Yeast within phagocyte
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What is used to diagnose a Penicilliosis marneffei infection?
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diagnosis based on typical Penicillium MOLD morphology with soluble RED pigment @ 25 C
Confirmation at transition to yeast |
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how do you treat a patient with Penicilliosis marneffei infection?
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Amphotericin B followed by itraconazole for weeks.
LIfetime chemotherapy with HIV patients |
