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Questions and Answers
What is a common serological test used for fungal infections?
What is a common serological test used for fungal infections?
- Latex agglutination (correct)
- Polymerase Chain Reaction (PCR)
- Acid-fast staining
- Gram staining
What is a common stain used in histopathology to visualize fungi in tissue samples?
What is a common stain used in histopathology to visualize fungi in tissue samples?
- Gomori methenamine silver (GMS) stain (correct)
- Ziehl-Neelsen stain
- Gram stain
- Wright stain
What is the optimal temperature for culturing pathogenic fungi?
What is the optimal temperature for culturing pathogenic fungi?
- 42 degrees C only
- Both 25 degrees C and 37 degrees C (correct)
- 37 degrees C only
- 25 degrees C only
Which of the following is NOT a reason for adding cyclohexamide, penicillin, or streptomycin to Sabouraud dextrose agar?
Which of the following is NOT a reason for adding cyclohexamide, penicillin, or streptomycin to Sabouraud dextrose agar?
What type of mycoses is caused by Malassezia furfur?
What type of mycoses is caused by Malassezia furfur?
Which of the following is a characteristic of the Sabouraud dextrose agar used for fungal culture?
Which of the following is a characteristic of the Sabouraud dextrose agar used for fungal culture?
Which of the following fungal infections is classified as cutaneous?
Which of the following fungal infections is classified as cutaneous?
What is the primary reason why serology is not always reliable for diagnosing fungal infections?
What is the primary reason why serology is not always reliable for diagnosing fungal infections?
Which of the following fungal species is NOT associated with mycetoma?
Which of the following fungal species is NOT associated with mycetoma?
What is the characteristic "Medlar bodies" associated with?
What is the characteristic "Medlar bodies" associated with?
Which fungal species is known to cause skin lesions after contact with a cat?
Which fungal species is known to cause skin lesions after contact with a cat?
Which of the following is NOT a clinical manifestation of chromoblastomycosis?
Which of the following is NOT a clinical manifestation of chromoblastomycosis?
Which of the following fungal species is associated with tinea unguium?
Which of the following fungal species is associated with tinea unguium?
Based on the provided information, which of these fungal species is associated with Tinea capitis?
Based on the provided information, which of these fungal species is associated with Tinea capitis?
Which of the following is NOT a typical characteristic of mycetoma?
Which of the following is NOT a typical characteristic of mycetoma?
What image type is associated with Malassezia furfur?
What image type is associated with Malassezia furfur?
What is the preferred growth temperature for the yeast form of Candida albicans?
What is the preferred growth temperature for the yeast form of Candida albicans?
What is the term used for the new budding cells that form on hyphae?
What is the term used for the new budding cells that form on hyphae?
What is the function of the septum in Candida albicans?
What is the function of the septum in Candida albicans?
What is the primary reason why Sabouraud's agar is commonly used for fungal cultures?
What is the primary reason why Sabouraud's agar is commonly used for fungal cultures?
What is the significance of the threshold volume in Candida albicans hypha formation?
What is the significance of the threshold volume in Candida albicans hypha formation?
Which of these is NOT a commonly used method for diagnosing fungal infections?
Which of these is NOT a commonly used method for diagnosing fungal infections?
Which of the following statements about Candida albicans is TRUE?
Which of the following statements about Candida albicans is TRUE?
What type of microscopy is used to visualize the unstained Candida albicans cells in the provided text?
What type of microscopy is used to visualize the unstained Candida albicans cells in the provided text?
Which of the following fungi is NOT responsible for causing a systemic fungal disease?
Which of the following fungi is NOT responsible for causing a systemic fungal disease?
What is the primary cell type involved in the formation of granulomas in response to fungal infections?
What is the primary cell type involved in the formation of granulomas in response to fungal infections?
Which of the following is NOT a typical characteristic of the fungal cell wall that contributes to the differences between bacterial and fungal infections?
Which of the following is NOT a typical characteristic of the fungal cell wall that contributes to the differences between bacterial and fungal infections?
Which of these is true regarding the use of skin tests for assessing fungal exposure?
Which of these is true regarding the use of skin tests for assessing fungal exposure?
Which of the following environmental factors is MOST favorable for mold growth as compared to bacteria?
Which of the following environmental factors is MOST favorable for mold growth as compared to bacteria?
Which of the following is NOT an example of a fungal disease that typically presents with acute suppuration characterized by the presence of neutrophils?
Which of the following is NOT an example of a fungal disease that typically presents with acute suppuration characterized by the presence of neutrophils?
Which of the following fungi is specifically mentioned as having a characteristic that limits its ability to infect the scalp during puberty?
Which of the following fungi is specifically mentioned as having a characteristic that limits its ability to infect the scalp during puberty?
Why are molds often involved in the spoilage of fruits, grains, vegetables and jams?
Why are molds often involved in the spoilage of fruits, grains, vegetables and jams?
Which of the following is NOT mentioned as a clinical presentation of Microsporum canis infection?
Which of the following is NOT mentioned as a clinical presentation of Microsporum canis infection?
What is the most likely cause of the tinea pedis described in the content?
What is the most likely cause of the tinea pedis described in the content?
Which of the following is NOT a characteristic of Epidermophyton floccosum?
Which of the following is NOT a characteristic of Epidermophyton floccosum?
What is the likely source of infection for the young boy with numerous, circular scaling lesions?
What is the likely source of infection for the young boy with numerous, circular scaling lesions?
Based on the information provided, which of the following statements is TRUE?
Based on the information provided, which of the following statements is TRUE?
Which of the following is NOT a common location for tinea cruris infections?
Which of the following is NOT a common location for tinea cruris infections?
What type of fungal infection would you suspect based on the following characteristics: infection of the hair shaft surface, presence of mycelium and spores on the hair shaft, and the absence of macroconidia?
What type of fungal infection would you suspect based on the following characteristics: infection of the hair shaft surface, presence of mycelium and spores on the hair shaft, and the absence of macroconidia?
How are subcutaneous mycoses typically acquired?
How are subcutaneous mycoses typically acquired?
Which fungal species is commonly associated with tinea unguium, an infection of the fingernails?
Which fungal species is commonly associated with tinea unguium, an infection of the fingernails?
What is the primary diagnostic tool for identifying the specific dermatophyte species causing a fungal infection?
What is the primary diagnostic tool for identifying the specific dermatophyte species causing a fungal infection?
Which of the following characterizes the growth pattern of subcutaneous mycoses?
Which of the following characterizes the growth pattern of subcutaneous mycoses?
Which of the following is NOT a characteristic of endothrix infections?
Which of the following is NOT a characteristic of endothrix infections?
What method is typically used to collect samples for the diagnosis of fungal infections of the skin and nails?
What method is typically used to collect samples for the diagnosis of fungal infections of the skin and nails?
Flashcards
Fungi in Food Production
Fungi in Food Production
Fungi are essential in making bread, cheese, wine, and beer.
Spoilage due to Fungi
Spoilage due to Fungi
Fungi can spoil fruits, grains, and jams due to their tolerance for drier and acidic conditions.
Granulomas
Granulomas
Granulomas are immune responses that form in systemic fungal infections.
Cell-mediated Immunity
Cell-mediated Immunity
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Hypersensitivity Skin Test
Hypersensitivity Skin Test
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Candida as Normal Flora
Candida as Normal Flora
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Intact Skin Defense
Intact Skin Defense
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Effects of Fatty Acids
Effects of Fatty Acids
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Mycelium
Mycelium
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Candida albicans
Candida albicans
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Budding yeast cells
Budding yeast cells
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Hypha formation
Hypha formation
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Germ tube
Germ tube
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Hyphal cells
Hyphal cells
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Sabouraud's agar
Sabouraud's agar
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Skin scrapings diagnosis
Skin scrapings diagnosis
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Epidermophyton sp
Epidermophyton sp
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Microsporum sp
Microsporum sp
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Trichophyton sp
Trichophyton sp
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Tinea cruris
Tinea cruris
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Tinea pedis
Tinea pedis
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Tinea unguium
Tinea unguium
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Ectothrix
Ectothrix
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Endothrix
Endothrix
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Serology
Serology
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Latex Agglutination
Latex Agglutination
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Double Immunodiffusion
Double Immunodiffusion
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Gomori Methenamine Silver (GMS) Stain
Gomori Methenamine Silver (GMS) Stain
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Culture
Culture
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Sabouraud Dextrose Agar
Sabouraud Dextrose Agar
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Superficial Mycoses
Superficial Mycoses
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Dermatophytosis
Dermatophytosis
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Microsporum canis
Microsporum canis
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Tinea corporis
Tinea corporis
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Epidermophyton floccosum
Epidermophyton floccosum
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Clavate conidia
Clavate conidia
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Fonsecaea pedrosoi
Fonsecaea pedrosoi
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Madurella mycetomatis
Madurella mycetomatis
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Tinea capitis
Tinea capitis
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Malassezia furfur
Malassezia furfur
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Onychomycosis
Onychomycosis
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Pseudallescheria boydii
Pseudallescheria boydii
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Study Notes
Mycology (I) - Introduction
- Mycology is the study of fungi
- Fungi are eukaryotic organisms, unlike bacteria which are prokaryotic
- Fungi lack chlorophyll and have cell walls
- Fungi are filamentous and produce spores
- Most fungi are obligate or facultative aerobes, meaning they need oxygen to thrive, but some can survive with or without it
- There are estimated to be between 100,000 to 200,000 species of fungi.
- Approximately 300 species are pathogenic to humans.
- Mycoses refer to fungal infections in humans.
Fungal Cell Structure
- Cell Wall: Primarily composed of chitin, not peptidoglycan like bacteria. This makes fungi resistant to some antibiotics like penicillin.
- N-acetylglucosamine: A component of chitin, a structural polysaccharide in fungal cell walls.
- β-glucan: A major polysaccharide in fungal cell walls. The target of the antifungal drug caspofungin.
- Cell Membrane: Contains ergosterol, unlike human cells which have cholesterol. This difference in membrane sterols is the basis for the selective action of some antifungal drugs, such as amphotericin B and azole drugs (e.g., fluconazole and ketoconazole).
Fungal Morphology
- Yeasts: Unicellular, reproduce asexually by budding
- Molds: Multicellular, filamentous structures called hyphae
- Hyphae: Grow by extending their tips. Some hyphae have cross-walls (septate hyphae), while others don't (nonseptate or coenocytic hyphae).
- Mycelium: A mass of hyphae
- Dimorphic fungi : Exist in two forms (yeast and mold) depending on environmental conditions (temperature).
Fungal Reproduction
- Some fungi reproduce sexually forming spores like zygospores, basidiospores, and ascospores.
- The classification of fungi is based on their sexual spores. Fungi that do not form sexual spores may be termed "imperfect".
- Common asexual modes of reproduction in fungi are conidia (asexual spores), arthrospores, chlamydospores, blastospores, and sporangiospores.
Fungal Toxins and Allergies
- Mycotoxicoses: Caused by ingested toxins from fungi (e.g., Amanita mushrooms).
- Amanitin, phalloidin are potent hepatotoxins.
- Amanitin inhibits RNA polymerase, preventing mRNA synthesis.
- Ergotism: caused by Claviceps purpurea, which produces alkaloids like ergotamine and lysergic acid diethylamide (LSD)
- Aflatoxins: produced by Aspergillus flavus. They damage liver and are suspected to cause hepatic carcinoma in humans.
- Allergies to fungal spores (e.g., Aspergillus) manifest as asthma, eosinophilia, and skin reactions.
Pathogenesis of Fungal Infections
- Granulomas: A common tissue response to fungal infections, especially in major systemic fungal diseases.
- Cell-mediated immune response is involved in granuloma formation.
- Acute suppuration may also occur in some fungal diseases (e.g., aspergillosis, sporotrichosis)
Fungal Classification
- Ascomycota: Sexual reproduction in a sac called an ascus
- Basidiomycota: Sexual reproduction in a sac called a basidium
- Zygomycota: Sexual reproduction with gametes and asexual reproduction resulting in zygospores
- Mitosporic Fungi (Fungi Imperfecti): No recognizable form of sexual reproduction and include many pathogenic species.
Clinical Classification of Mycoses
- Superficial: Infections confined to outer layers of skin, hair, or nails (example: pityriasis versicolor)
- Cutaneous: Infections involving skin, hair, and nails (example: dermatophytosis)
- Subcutaneous: Infections confined to subcutaneous tissues (example: sporotrichosis)
- Systemic: Infections affecting internal organs (example: histoplasmosis)
- Opportunistic: Infections in immunocompromised individuals (example: candidiasis)
Diagnostic Methods
- Skin scrapings
- Skin testing (dermal hypersensitivity)
- Serology (latex agglutination, double immunodiffusion)
- Direct fluorescent microscopy
- Biopsy and histopathology
- Culture (Sabouraud dextrose agar)
Fungal Growth and Isolation
- Fungi grow readily on simple sources of nitrogen and carbohydrates.
- Sabourad's agar is a common medium for cultivating fungi due to its low support of bacterial growth.
Epidemiology and Control of Fungal Infections
- Transmission of dermatophytes is often through direct contact with infected skin or hair.
- Control of fungal infections involves proper hygiene, sterilization, and prompt treatment of affected individuals.
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Description
Test your knowledge about fungal infections with this comprehensive quiz. Covering serological tests, culture methods, and specific fungal diseases, this quiz will challenge your understanding of mycology and its clinical applications. Perfect for students in health sciences or microbiology.
