Medical Mycology Quiz: Candida and Cryptococcus
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Questions and Answers

Which of the following genera of fungi is NOT medically important?

  • Streptococcus (correct)
  • Aspergillus
  • Candida
  • Cryptococcus

    • Candida glabrata is less drug resistant than Candida albicans.

    False

    What is the most important species of the Candida genus?

    Candida albicans

    Candidemia refers to _____ infections.

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

    Which condition is a common disease caused by Candida albicans?

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

    Match the following Candida species with their characteristics:

    <p>Candida albicans = Forms pseudohyphae and true hyphae Candida glabrata = More drug resistant than C.albicans Candida dubliniensis = Grows at 42°C Candida tropicalis = Differentiated by carbohydrate fermentation reactions</p> Signup and view all the answers

    What is the first line of defense against Candida infections?

    <p>Intact skin and mucous membranes</p> Signup and view all the answers

    Candida albicans can cause _____ infections related to indwelling catheters.

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

    What type of capsule surrounds Cryptococcus neoformans?

    <p>Thick polysaccharide capsule</p> Signup and view all the answers

    Cryptococcus gattii is less capable of causing disease in immunocompetent individuals than Cryptococcus neoformans.

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

    What test is abbreviated as 'crag'?

    <p>Cryptococcal antigen test</p> Signup and view all the answers

    Aspergillus species exist only as ______.

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

    Match the following conditions with the responsible species:

    <p>Cryptococcus neoformans = Meningitis Cryptococcus gattii = Cryptoccomas Aspergillus fumigatus = Fungus ball in lungs Aspergillus species = Allergic bronchopulmonary aspergillosis</p> Signup and view all the answers

    Which statement about the transmission of Cryptococcus neoformans is true?

    <p>It is commonly found in soil with bird droppings.</p> Signup and view all the answers

    The appearance of Aspergillus species cells can be reliably visualized using Gram stain.

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

    What is the primary treatment for cryptococcal infections?

    <p>Amphotericin B and flucytosine</p> Signup and view all the answers

    Which pathogenic species is known to form germ tubes at 37°C?

    <p>Candida albicans</p> Signup and view all the answers

    Chlamydospores are formed by most other species of Candida.

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

    What laboratory test can identify Candida albicans and four other species in blood cultures within 3 to 5 hours?

    <p>A test using magnetic resonance technology.</p> Signup and view all the answers

    Treatment for esophageal candidiasis includes an echinocandin such as ________ or micafungin.

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

    Which drug can be used to prevent certain candidal infections like thrush?

    <p>Clotrimazole troches</p> Signup and view all the answers

    Individuals who do not respond to Candida antigens in the skin test are considered anergic.

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

    Match the following drugs with their corresponding treatment purposes:

    <p>Fluconazole = Thrush Caspofungin = Esophageal Candidiasis Clotrimazole = Skin Infections Miconazole = Candida Vaginitis</p> Signup and view all the answers

    Which species of Cryptococcus causes the most common life-threatening invasive fungal disease?

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

    What role do Th-1 cells play in cell-mediated immunity?

    <p>They produce gamma-interferon activating macrophages</p> Signup and view all the answers

    Neutrophils are not significant in combating Candida infections.

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

    What condition is characterized by white patches in the mouth due to overgrowth of Candida albicans?

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

    High pH, diabetes, or the use of antibiotics can lead to _____, a condition that includes itching and discharge.

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

    Match the condition with its description:

    <p>Thrush = White patches in the mouth Diaper rash = Occurs from wet diapers not being changed promptly Chronic mucocutaneous candidiasis = Prolonged infection affecting skin and mucosa Candida esophagitis = Involvement of the esophagus in immunocompromised patients</p> Signup and view all the answers

    Which factor is NOT associated with an increased risk of disseminated Candida infections?

    <p>Regular exercise</p> Signup and view all the answers

    Candida esophagitis mainly occurs in healthy individuals.

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

    What type of staining can help visualize budding yeasts and pseudohyphae in tissue samples?

    <p>calcofluor-white staining</p> Signup and view all the answers

    What is the most common fungal cause of sinusitis?

    <p>Aspergillus fumigatus</p> Signup and view all the answers

    Aspergillus species can only colonize healthy skin and do not invade compromised tissues.

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

    What is the primary drug used to treat invasive aspergillosis?

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

    The fungus ball produced by Aspergillus in lung cavities is known as an ______.

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

    Match the following treatments with their respective conditions:

    <p>Voriconazole = Invasive aspergillosis Corticosteroids = Allergic bronchopulmonary aspergillosis Liposome amphotericin B = Invasive aspergillosis Itraconazole = Allergic bronchopulmonary aspergillosis</p> Signup and view all the answers

    Which condition is characterized by a hypersensitivity reaction to Aspergillus?

    <p>Allergic bronchopulmonary aspergillosis (ABPA)</p> Signup and view all the answers

    Mucormycosis is caused by dimorphic fungi.

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

    What type of patients are most at risk for infections caused by Aspergillus species?

    <p>Immunocompromised patients</p> Signup and view all the answers

    What is the primary cause of about 60% of mucormycosis cases?

    <p>Rhizopus oryzae</p> Signup and view all the answers

    Pneumocystis jiroveci is classified as a yeast and has characteristics of both yeast and protozoan.

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

    What is the primary method of transmission for Pneumocystis pneumonia?

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

    In patients with preexisting kidney damage, __________ should be used to treat mucormycosis.

    <p>liposomal amphotericin B</p> Signup and view all the answers

    What is commonly observed on a chest X-ray of a patient with Pneumocystis pneumonia?

    <p>Ground glass pattern</p> Signup and view all the answers

    Match each organism with its description.

    <p>Rhizopus oryzae = Causes 60% of mucormycosis cases Pneumocystis jiroveci = Yeast-like organism causing pneumonia Sporothrix schenckii = Dimorphic fungus found in plants Trimethoprim-sulfamethoxazole = Prophylactic treatment for Pneumocystis pneumonia</p> Signup and view all the answers

    Serological tests are useful for diagnosing Pneumocystis pneumonia.

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

    What is the mortality rate of untreated Pneumocystis pneumonia?

    <p>Approximately 100%</p> Signup and view all the answers

    Study Notes

    Opportunistic Mycoses

    • Opportunistic fungi cause disease in individuals with weakened immune systems.
    • Five medically important fungal genera are: Candida, Cryptococcus, Aspergillus, Mucor, and Rhizopus.

    Candida

    • Species: Candida albicans is the most significant species, causing thrush, vaginitis, and other infections. Candida glabrata is another important species.
    • Forms: Candida albicans appears as yeast or pseudohyphae in tissues.
    • Properties: Candida is part of the normal flora in the upper respiratory, gastrointestinal, and genital tracts.
    • Transmission: Candida is naturally present on skin and mucous membranes. Transmission occurs through contact or via passage through a colonized birth canal. Infections can also occur through instruments that penetrate the skin.
    • Pathogenesis/Clinical Findings: Intact skin and mucous membranes act as a first line of defense. The second line is cell-mediated immunity (Th-1 cells producing gamma-interferon). Neutrophils are important for killing pathogens; neutropenia increases the risk of disseminated infections. Impaired host defenses lead to overgrowth. Thrush (white patches) in the mouth is a common clinical manifestation. Vaginitis can result from high pH and antibiotic usage. Skin infections can appear in moist areas, like diaper rash. Infections in immunocompromised individuals can disseminate to multiple organs, leading to chronic mucocutaneous candidiasis.
    • Laboratory Diagnosis: Gram-positive, culture-grown yeast colonies, germ tubes (if Candida albicans), India ink stain, capsule presence, etc.
    • Treatment/Prevention: Various antifungal medications like fluconazole, itraconazole, and nystatin are used to treat Candida infections. Oral clotrimazole troches or clotrimazole creams can be used as a preventive method.

    Cryptococcus

    • Species: Cryptococcus neoformans is the major cause of cryptococcosis, especially cryptococcal meningitis. A less frequent causative agent is Cryptococcus gattii.
    • Properties: Oval, budding yeast cells with a wide polysaccharide capsule.
    • Transmission: Occurs widely in nature (e.g., bird droppings) and can be inhaled by individuals.
    • Diagnosis: Use of India ink (visualizing the capsule); microscopic evaluation of CSF (spinal fluid).
    • Treatment: Combination of amphotericin B and flucytosine is common. Prophylaxis is also an option for AIDS patients with low CD4 cell counts and fluconazole use is often included as a prophylactic measure
    • Properties:

    Aspergillus

    • Species: Aspergillus fumigatus is a prevalent species, and commonly causes infections, like "fungus ball" formation in the lung and allergic bronchopulmonary aspergillosis.
    • Properties: Mold form only; it is not dimorphic.
    • Transmission: Airborne conidia, as the fungus grows on decaying vegetation.
    • Pathogenesis: Aspergillus can colonize and invade abraded skin, wounds, and the eyes. Neutropenic patients are particularly vulnerable; cavities in the lung (e.g., from tuberculosis) are common locations for aspergilloma formation.
    • Treatment: Voriconazole is the typical treatment. Other alternatives like liposomal amphotericin B, posaconazole, and caspofungin are also available. Surgery may be used to remove a fungus ball.

    Mucor/Rhizopus

    • Species: Common species include Rhizopus and Mucor. These organisms cause mucormycosis.
    • Properties: Non-dimorphic molds. Hyphae are broad, non-septate (lacking cross-walls). These hyphae grow rapidly and invade blood vessels, leading to infarction and necrosis.
    • Transmission: The fungi are widely found in the environment in decaying vegetative matter.
    • Treatment: Amphotericin B and surgical removal of necrotic infected tissue are common therapies.

    Pneumocystis

    • Species: Pneumocystis jiroveci causes pneumonia, commonly in immunocompromised individuals (e.g., AIDS patients)
    • Properties: Yeast-like organism with characteristics of protozoa. Detected as small organisms via microscopic analysis.
    • Transmission: Airborne transmission.
    • Treatment: Trimethoprim-sulfamethoxazole or aerosolized pentamidine are used for prophylaxis in patients with low CD4 counts, and for treatment.

    Sporothrix

    • Species: Sporothrix schenckii causes sporotrichosis.
    • Properties: Dimorphic fungus (mold in some situations and yeast in others). Found in the environment around plants and soil.
    • Transmission: Cutaneous inoculation from infected material, e.g., rose thorns.
    • Treatment: ITraconazole is the common therapy for cutaneous sporotrichosis. More extensive disease may require more aggressive antifungal therapy (e.g., amphotericin B).

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    Opportunistic Fungi PDF

    Description

    Test your knowledge on medically important fungi, focusing on Candida and Cryptococcus species. This quiz covers characteristics, infections, and treatment related to these genera. Ideal for students in microbiology or healthcare fields.

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