Systemic Mycoses: Dimorphic Fungi Overview
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Questions and Answers

What is the most virulent systemic fungus among the options provided?

  • Blastomyces dermatitidis
  • Cryptococcus neoformans
  • Coccidioides immitis (correct)
  • Histoplasma capsulatum
  • Which systemic fungal infection is characterized by nodules and cavitary lung disease?

  • Cryptococcosis
  • Blastomycosis
  • Coccidioidomycosis (correct)
  • Histoplasmosis
  • In which phase does Blastomyces dermatitidis show single, circular to pyriform conidia produced on short conidiophores?

  • Spherule phase
  • Endospore phase
  • Mold phase (correct)
  • Yeast phase
  • Which systemic fungal infection is associated with Filipinos, blacks, males, and pregnant women?

    <p>Coccidioidomycosis</p> Signup and view all the answers

    What is the diagnostic method that demonstrates characteristic broad-based budding yeast for Blastomyces dermatitidis?

    <p>Auramine-rhodamine stain</p> Signup and view all the answers

    Which systemic fungal infection is known to require inhalation of infective arthroconidia for transmission?

    <p>Coccidioidomycosis</p> Signup and view all the answers

    Which of the following is a characteristic feature of Penicillium marneffei mold phase?

    <p>Produces red diffusible pigment</p> Signup and view all the answers

    What is a common result of disseminated Penicillium marneffei infection?

    <p>Meningeal involvement</p> Signup and view all the answers

    How is Penicillium marneffei transmitted to humans?

    <p>Inhalation of arthroconidia</p> Signup and view all the answers

    Which symptom is NOT typically associated with primary Penicillium marneffei infection?

    <p>Meningitis</p> Signup and view all the answers

    What is the most effective method for preventing systemic fungal infections like Penicillium marneffei?

    <p>Wearing masks in contaminated areas</p> Signup and view all the answers

    Which diagnostic method is commonly used to identify systemic fungal infections like Penicillium marneffei?

    <p>Fungal cultures from sputum or tissue samples</p> Signup and view all the answers

    What is the most common mode of transmission for Blastomyces dermatitidis?

    <p>Inhalation of conidia/ hyphae</p> Signup and view all the answers

    What are the typical organs or body systems affected by blastomycosis caused by Blastomyces dermatitidis?

    <p>Lungs, bones, skin, soft tissue</p> Signup and view all the answers

    Which of the following is a common feature of systemic mycoses caused by dimorphic fungi?

    <p>Asymptomatic course in most cases</p> Signup and view all the answers

    What is the primary method for the identification of dimorphic fungi causing systemic mycoses?

    <p>Colonial morphology and microscopic characteristics</p> Signup and view all the answers

    Which of the following is NOT a type of dimorphic fungi associated with systemic mycoses?

    <p>Cryptococcus neoformans causing cryptococcosis</p> Signup and view all the answers

    What are the preferred methods of treatment for systemic fungal infections caused by dimorphic fungi?

    <p>Antifungal medications like Amphotericin B and Itraconazole</p> Signup and view all the answers

    Study Notes

    Systemic Mycoses

    • Systemic mycoses are fungal infections that may involve any internal organs
    • Mostly asymptomatic, dimorphism is common, and slow-growing organisms
    • Identified by growth characteristics, colonial morphology, microscopic characteristics of conidia and hyphae, cultivation, and serologic testing

    Blastomyces dermatitidis

    • Causes blastomycosis
    • Found in soil or wood in Canada, Mississippi, Missouri, Ohio River Valleys, Mexico, and Southern USA
    • Affects males, especially those in outdoor occupations/activities
    • Mode of transmission: inhalation of conidia/ hyphae
    • Begins as a respiratory infection, may cause chronic infection in lungs, bones, skin, and soft tissue
    • Lesions and ulcerations occur

    Yeast Phase of Blastomyces dermatitidis

    • Thick-walled oval to round, single-budding, yeastlike cells
    • KOH preparation of exudates shows a large budding yeast cell with a distinct broad base between the cells
    • Auramine-rhodamine stain of specimen from bone lesion demonstrates characteristic broad-based budding yeast

    Mold Phase of Blastomyces dermatitidis

    • Single, circular to pyriform conidia produced on short conidiophores that resemble lollipops
    • Glabrous or waxy-appearing, off-white to white
    • Spicules —> center
    • Mold-to-yeast conversion usually requires 4-5 days
    • Mycelial form shows oval conidia borne laterally on branching hyphae

    Coccidioides immitis

    • Causes coccidioidomycosis, also known as "Desert Fever" or "Valley Fever"
    • Affects Filipinos and blacks, especially males and pregnant women
    • Mode of transmission: inhalation of infective arthroconidia
    • Can cause asymptomatic, self-limited infections or allergic manifestations, and nodules and cavitary lung disease

    Yeast Phase of Coccidioides immitis

    • Spherules contain endospores
    • External wall of the spherule does not stain with silver stain, whereas internal endospores do

    Mold Phase of Coccidioides immitis

    • Shows septate hyphae and pyriform conidia singly borne

    Penicillium marneffei

    • Causes systemic penicillosis, especially in immunocompromised patients with AIDS, hematologic malignancies, autoimmune disease, or organ transplantations
    • Found in Southeast Asia
    • Can cause disseminated infection with multiple organ involvement
    • Fatal if left untreated
    • Yeast-like cells resemble those of H. capsulatum

    Mold Phase of Penicillium marneffei

    • Produces a red diffusible pigment

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    Description

    Explore the characteristics of systemic mycoses caused by dimorphic fungi, focusing on the yeast and mold phases, their growth conditions, and where they are commonly found. Learn about the manifestations and slow-growing nature of these fungal infections.

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