Mycology Flashcards
What is a Blastoconidia?
Budding yeast cell
Asexual spores produced with a spherule are called…
Endospores
Endemic mycoses are dimorphic and spread by inhalation of spores. What form of fungi is transmissible? Is person-to-person transmission possible?
Mold is the infectious form and found in soil. Yeast is present in tissues during infection, but is non-infectious so person-to-person spread is not possible.
Hyphae with cross walls are said to be…
Septated
What disease is caused by Madurella mycetomatis or Pseudallescheria boydii? How does the disease present?
Mycetoma - starts as a small, firm, painless nodule. Spreads to fascia and bone causing subcutaneous abscesses
Conidia and sporangiospores are asexual fungal spores. What is the difference between the two?
Conidia extend openly from conidiophores. Sporangiospores extend from a sporangium and are enclosed in a sac-like structure.
Describe the life cycle of Pneumocystis.
Intracystics bodies within cysts rupture and release trophs. Trophs divide by fission or fuse (sexual reproduction) to form new cysts.
These terms describe structures that contain 1 or more conidia.
Microconidia (small) & macroconidia (large)
A fungus is cultured and grown at room temperature. What form of fungi will predominate? What will happen if the temperature of the culture is raised to 37oC?
At room temperature, the mold form of growth predominates. At 37oC, the yeast form of mold predominates and fungi will resemble bacterial colonies.
What types of infections may be caused by Aspergillus spp.?
Allergic reactions, colonization of body cavities, infections of wounds and catheters, invasion of respiratory system
What is the clinical appearance of Pneumocystis pneumonia?
Fever, dyspnea, dry and nonproductive cough, hypoxemia, foamy and eosinophilic exudate. AIDS-defining illness
Another term for fungal spores is…
Conidia
This form of fungi is filamentous
Mold
What is white piedra? What fungus is the cause of disease?
Soft nodules along the hair shaft caused by Trichosporon ovoides
Sabouraud’s agar haw a low pH to inhibit bacterial growth. When is this agar primarily used?
For culturing of dermatophytes (fungi that infect keratinized tissue)
Sporothrix schenckii is common in the USA. What are the characteristics of the fungus? What populations are generally infected? How does disease appear clinically?
Dimorphic found in soil and plants, commonly infecting gardeners, florists, farmers, etc.
Disease is called Sporotrichosis appearing as a painless papule at the site of inoculation and slowly enlarges to an open sore. The fungus may spread via lymphatics.
What are the characteristics of Cryptococcus?
Non-dimorphic, encapsulated yeast found in soil contaminated by pigeon droppings. Transmission via aerosols.
What are the characteristics of Aspergillus spp.?
Septated hyphae with chains of conidia on a conidiophore. Mold in soil and plants, transmission via spores
How can dermatophytes be differentiated based on appearance?
Microsporum spp. - contain macroconidia
Trichophyton spp. - microconidia & macroconidia
Epidermophyton floccosum - microconidia
What agar is used as a differential media for Canida spp.?
CHROMager
Acidotic diabetic patients are more susceptible to what infection by what systemic fungus?
Rhinocerebal disease - Mucormycetes genera
What fungus is responsible for causing Tinea nigra (brown to black lesions on hands and feet)? How is the fungus spread? How does it appear in culture?
Hortaea werneckii spread by soil, compost, and wood. Appears with brown septated hyphae and 2-celled yeast cells