Fungal CBL Flashcards
Describe the mode of action of anole drugs. What fungal infections are they used to treat?
Azole antifungals inhibit Cytochrome P450-dependent enzyme lanosterol 14-alpha-demethylase that catalyzes lanosterol to ergosterol. Fluconazole protects patients against YEASTS.
Describe the mode of action of Nystatin. What infections is this used to treat?
This ionophore binds ergosterol and creates pores for K+ leakage and acidification of fungus. Used to treat Candida albicans.
What is the recommended treatment for cryptococcal meningitis? What are some alternatives?
Flucanazole;
Flucytosine, amphotericin
What is the principal drug of choice for pneumocystic pneumonia?
Pentamidine
What fungus displays dimorphism when observed by definitive diagnosis?
Sporothrix schenckii;
exists as a cigar-shaped yeast inside host (35 - 37 C), but a branching hyphae in outside environments (25 C)
What is the drug of choice to treat lymphocutaneous sporotrichosis (caused by sporothrix schenckii)
Itraconazole or Potassium solution (of potassium iodide)
What is the drug of choice to treat an infection of Aspergillus Fumigatus.
Caspofungin
What is the antifungal drug of choice to treat a Candida albicans infection?
Nyastatin - applied topically to treat mucocutaneous candidiasis
This fungus creates white patches on the lining of the oral cavity when infecting a patient. A smear of the scraping reveals budding yeasts + pseudohyphae, BUT it forms elongating buds in plasma culture. What is this?
Candida albicans
What phase structures do Candida albicans fungi form on commeal agar?
Hyphae or pseudohyphae, microconidia and chlamydospores
What is the clear histological feature of a stained smear of leukocytes from the yeast infection of Histoplasma capsulatum?
“Buffy coat” of intracellular yeast forms in the stained blood smear of H. Capsulatum infection.
A gardener develops a slow-growing nodule on his forearm that turns into an ulcerated lesion. Microscopy of the infection in the serum reveals elongate budding yeast that DO NOT form germ tubes. What is the fungus?
Sporothrix schenckii
Where can someone contract Histoplasma capsulatum fungal infection?
Caves, bird/bat droppings in the Midwestern US.
What are the 2 ways to diagnose a Histoplasma capsulatum fungus?
Rapid serum antigen (red) test or Urine Antigen test (yellow).
Describe the general forms of dimorphic pathogenic fungi.
“Mold in the cold. Yeast in the heat.” In the environment, many fungi such as Sporothrix schenckii grow hyphae (25 C); whereas, in the body they become budding yeasts (35 C).