Subcutaneous Mycoses and Chromoblastomycosis Quiz
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Questions and Answers

What are the primary clinical manifestations of progressive pulmonary disease caused by systemic mycoses?

Cough, weight loss, chest pain, and fever.

What are the two species of Blastomyces responsible for blastomycosis?

Blastomyces dermatitidis and Blastomyces gilchristii.

How can systemic mycoses lead to skin and bone complications?

It results in ulcerative lesions of the skin and bone.

What is the geographic distribution of blastomycosis?

<p>It primarily occurs in North America and parts of Africa.</p> Signup and view all the answers

What makes Coccidioides one of the most virulent mycotic agents?

<p>It is considered the probable most virulent of all human mycotic agents.</p> Signup and view all the answers

What are the budding yeast cells characteristics seen in cutaneous and mucosal lesions for patients with immunocompromised conditions?

<p>They are 15 to 30 μm in diameter and exhibit multipolar budding resembling a 'mariner’s wheel.'</p> Signup and view all the answers

What are some clinical manifestations of chronic pulmonary histoplasmosis in patients with COPD?

<p>It can lead to reticuloendothelial cytomycosis and may cause signs similar to tuberculosis due to granuloma formation.</p> Signup and view all the answers

How is Histoplasma capsulatum identified in laboratory diagnosis?

<p>It is identified by direct microscopic morphology when yeast cells are stained with Giemsa or Wright stain.</p> Signup and view all the answers

Describe the distribution and endemicity of Histoplasma capsulatum.

<p>Histoplasma capsulatum has a worldwide distribution with the highest endemicity in the Ohio, Missouri, and Mississippi river deltas.</p> Signup and view all the answers

What morphological changes occur to the mycelium of Histoplasma capsulatum as it matures?

<p>The mycelium initially appears white but turns gray or gray-brown as the colony matures.</p> Signup and view all the answers

What does the clustered appearance of yeast cells in tissue suggest in histoplasmosis?

<p>It suggests the presence of yeast cells within macrophages, appearing pseudo-encapsulated.</p> Signup and view all the answers

List some alternative names for histoplasmosis.

<p>It is also known as cave disease, spelunker’s disease, and Darling disease.</p> Signup and view all the answers

What are the possible severe outcomes of disseminated histoplasmosis in immunocompromised patients?

<p>It can lead to progressive and potentially fatal disseminated disease.</p> Signup and view all the answers

What is a primary characteristic of the hyphae observed in Mucorales?

<p>They are broad, irregular in width, ribbon-like, and aseptate.</p> Signup and view all the answers

Describe the typical morphology of Syncephalastrum colonies.

<p>They exhibit a woolly appearance and change color from white to gray or brown with age.</p> Signup and view all the answers

How do rhizoids in Mucorales differ from those in Rhizopus spp.?

<p>Mucorales have internodal rhizoids that originate from hyphae between the conidiophores and are more delicate.</p> Signup and view all the answers

What is the unique feature of sporangiophores in some Mucorales?

<p>They can collapse umbrella-like after maturing.</p> Signup and view all the answers

What color variations are commonly observed in pathogenic species of Mucorales?

<p>They form colonies that are green to tan in color.</p> Signup and view all the answers

What type of arrangement do merosporangia have in Syncephalastrum?

<p>Merosporangia are cylindric and arranged in 'daisy petals' around a small spherical columella.</p> Signup and view all the answers

Identify a key ecological niche where Mucorales are commonly found.

<p>They are found in soil, dung, and decomposing organic matter.</p> Signup and view all the answers

What notable feature allows some species of Mucorales to produce pigments?

<p>Some species possess diffusible subsurface pigments that can be seen on various media.</p> Signup and view all the answers

What is the primary mode of transmission for coccidioidomycosis?

<p>Inhalation of only a few arthroconidia.</p> Signup and view all the answers

What are the preferred specimens for laboratory diagnosis of primary coccidioidomycosis?

<p>Tissue or purulent material from cutaneous skin lesions.</p> Signup and view all the answers

What are some types of clinical infections associated with coccidioidomycosis?

<p>Asymptomatic pulmonary disease and allergic manifestations.</p> Signup and view all the answers

What microscopy techniques can enhance the detection of yeast cells in coccidioidomycosis?

<p>KOH (10%) or calcofluor white may be used.</p> Signup and view all the answers

Describe the morphology of the mold phase for coccidioidomycosis.

<p>Conidia are borne on short lateral branches and are ovoid to dumbbell-shaped, varying from 2 to 10 μm in diameter.</p> Signup and view all the answers

What clinical conditions may arise as allergic manifestations from coccidioidomycosis?

<p>Toxic erythema, erythema nodosum, and arthritis.</p> Signup and view all the answers

What characteristic finding in microscopy can suggest a diagnosis of coccidioidomycosis?

<p>Large, spherical, refractile yeasts with double-contoured walls.</p> Signup and view all the answers

What evidence of strong immunity to reinfection can be detected in individuals with coccidioidomycosis?

<p>The coccidioidin skin test.</p> Signup and view all the answers

What is a characteristic appearance of Cladosporium conidia?

<p>Cladosporium conidia display a shield-like appearance.</p> Signup and view all the answers

How are Curvularia conidia typically structured?

<p>Curvularia conidia are often crescent-shaped and can have three to five cells of unequal size.</p> Signup and view all the answers

In what type of patients is Curvularia commonly associated with chronic sinusitis?

<p>Curvularia is often associated with chronic sinusitis in immunocompromised patients.</p> Signup and view all the answers

What is the reproductive characteristic that differentiates true yeasts from yeastlike fungi?

<p>True yeasts reproduce sexually by forming ascospores or basidiospores.</p> Signup and view all the answers

What type of conidiophores do Curvularia produce?

<p>Curvularia produces multicelled conidia on sympodial conidiophores.</p> Signup and view all the answers

What color variations can be observed in the hyphae of Cladosporium?

<p>Cladosporium hyphae can appear in colors ranging from brown to olive to black.</p> Signup and view all the answers

What does an increased incidence of yeast infections indicate in clinical settings?

<p>An increased incidence provides evidence for identifying yeasts at the species level.</p> Signup and view all the answers

What distinguishes yeastlike fungi from true yeasts?

<p>Yeastlike fungi are isolates not capable of sexual reproduction.</p> Signup and view all the answers

What diagnostic methods are primarily used to identify Cryptococcus neoformans?

<p>The India ink test and cryptococcal antigen tests are primarily used.</p> Signup and view all the answers

What characteristic appearance does Cryptococcus neoformans have when viewed under UV light?

<p>It has a blue-white color when stained and viewed under ultraviolet light.</p> Signup and view all the answers

What is the significance of blastoconidia in the characterization of Cryptococcus?

<p>Blastoconidia are the only form seen in Cryptococcus, indicating its yeast nature.</p> Signup and view all the answers

What type of infections is Cryptococcus neoformans primarily associated with?

<p>It is primarily associated with opportunistic infections like meningitis and pneumonia.</p> Signup and view all the answers

What is the appearance of Pneumocystis jirovecii cysts when stained with silver stain?

<p>Pneumocystis jirovecii cysts appear distinct and are visible under silver staining.</p> Signup and view all the answers

What does the term 'mucoid appearance' refer to in the context of Cryptococcus?

<p>It refers to the organism's appearance due to its protective capsule.</p> Signup and view all the answers

How can Cryptococcus be visualized in cerebrospinal fluid?

<p>Cryptococcus can be visualized using an India ink preparation from cerebrospinal fluid.</p> Signup and view all the answers

Which staining methods are mentioned for diagnosing Trichosporon species?

<p>Giemsa stain and Grocott's methenamine silver (GMS) stain are mentioned.</p> Signup and view all the answers

Study Notes

Subcutaneous Mycoses

  • Affect subcutaneous tissue
  • Usually result from foreign objects implanting into the skin, allowing fungi from soil or decaying matter to enter the host.
  • Causative organisms are commonly found in soil or decaying vegetation.
  • Infections are categorized based on the disease process they cause.
  • Chromoblastomycosis, a fatal fungal infection, is prevalent in Arizona and California.
  • Other types of chromoblastomycosis include verrucous dermatitidis and nodules that become ulcerated or crusted.
  • Chronic infection typically develops months to years after traumatic inoculation.

Chromoblastomycosis Manifestations

  • Lesions can manifest in various ways, including:
    • Lower leg lesion (lasting 3 months)
    • Confluent nodular lesions (on the knee)
    • Cauliflower-like or tumor-like lesions
    • Lesions with serpiginous and verrucous contours (showing scarring)

Chromoblastomycosis Diagnosis

  • KOH (10-40%) analysis
  • Histopathology (finding muriform cells, which are sclerotic bodies. These are usually 5-12 micrometers in diameter.)
  • Direct mycological examination
  • Immunodiagnosis

Agents of Chromoblastomycosis

  • Cladophialophora: Septate hyphae found inside tissue, and hyphae can be found in joints.
  • Phialophora: Sclerotic bodies and hyphae are present in the subcutaneous tissue.
  • Fonsecaea: Sclerotic bodies are observed in subcutaneous and lung tissue

Additional Information

  • ELISA is used to identify the presence of specific antigens from chromoblastomycosis
  • Microscopic morphology of various fungi causing chromoblastomycosis is detailed in table 27-2, showing characteristics like conidiogenous cells, conidia, and conidiophores.

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Mycology and Virology Midterms PDF

Description

Test your knowledge on subcutaneous mycoses, particularly chromoblastomycosis, and its manifestations. This quiz covers the causative organisms, clinical presentations, and diagnostic techniques associated with this fungal infection. Learn how environmental factors contribute to the disease process and explore the various lesions that can develop over time.

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