Immunological System Pathology 1 - Mycology Flashcards
What is the common name for the clinical presentation of Coccidiodes immitis or Coccidiodes posadasii infection?
San Joaquin Valley fever, formally coccidioidomycosis
From what do fungi derive their energy, and how is this different from plants?
From organic chemicals, primarily saccharides, unlike photosynthesis in most plants.
Residence in what region of North America is a risk for contracting coccidioidomycosis?
Southwestern US, Northwestern Mexico, and Central America
Residence in what region of North America is a risk for contracting histoplasmosis?
Northeastern US in Ohio and Mississippi river valleys
Residence in what region of North America is a risk for contracting Blastomycosis?
States bordering the Mississippi and Ohio rivers and those states and provinces bordering the Great Lakes and St. Lawrence River
What is the most common clinical presentation for someone infected with Coccidiodes immitis?
Flu-like illness (fever, chest pains, cough, and weight loss)
Who is most likely to develop serious complications or meningial involvement if infected with Coccidiodes immitis?
Immunodeficient individuals, pregnant women, those with blood group B, and those of African and Filipino descent
What are the acute symptoms of a Blastomy-cosis infection?
Looks like a bacterial pneumonia (myalgia, arthralgia, chills, fever, and cough) potentially with bone, skin, or male genitourinary involvement
What are the acute symptoms of a Histoplasmosis infection?
Mild flu-like illness (fever, headache, malaise, pleuritic chest pain, and nonproductive cough)
Which primary fungal infection has primary lung involvement with secondary mucosal lesions?
Paracoccidioidomycosis cause by Paracoccidioides brasiliensis
How do yeast reproduce?
Asexual budding
How do molds reproduce?
Spores, can be formed by meiosis (sexually) or mitosis (asexually)
What is the tubular branching network of a mold technically called?
Mycelium or colony
What is the name of the tubular branches of a mold
Hyphae and Pseudohyphae
What are the two types of Hyphae?
Coenocytic (hollow and multinucleate)
Septate (Septate contains groups of cells surrounded by a tubular cell wall and divided by a porous septum which allows for the sharing of cytoplasm and organelles)
How do pseudohyphae and hyphae differ?
Pseudohyphae do not share cytoplasm or organelles between cells
Do yeast contain hyphae?
No, they are unicellular
How can a mold be differentiated from a yeast under the microscope, and can an organism switch between the two forms?
Mold has hyphae, yeast are single rounded cells; and organism can switch between them or at least go between a yeast form and a pseudohyphae-forming form.
What substance predominates in the fungal cell wall?
Chitin
What steroidal substances predominates in the fungal plasma membrane?
Ergosterol. This serves a similar function of cholesterol in animal cells.
What medically important fungus is an obligate anaerobe?
None! (unlike bacteria)
What primary fungal pathogen is associated with bat and bird feces?
Histoplasma capsulatum
What opportunistic fungal pathogen is associated with bird feces?
Cryptococcus neoformans
What large capsulated yeast is commonly found in pigeon droppings?
Cryptococcus neoformans
Dermatophytes survive by obtaining nutrients from what?
Keratin
How is Tinea diagnosed?
Koh wet mount, Wood’s light or Fungal culture
How is Candida diagnosed?
Gram stain, Koh wet mount, vaginal pH, and skin biopsy
What opportunistic yeast most commonly overgrows in immunocompromised patients?
Candida albicans
How do you differentiate between a cutaneous Candida and Tinea infection?
Candida affects skin folds and the scrotum and has satellite lesions versus Tinea corporis doesn’t affect skin folds and Tinea crusis doesn’t affect the scrotum
What organisms cause jock itch (tinea cruris)?
Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum
What organism causes tinea barbae?
Trichophyton verrucosum
Chronic histoplasmosis can clinically resemble what other infectious disease?
Tuberculosis
What is the purpose of adding potassium hydroxide (koh) to wet mounts?
Dissolves human skin while leaving yeast cells intact.
What is the purpose of using India Ink?
It is used primarily to detect Cryptococcus spps.
