Dimorphic fungi Flashcards
(22 cards)
What is the defining feature of dimorphic fungi?
they have the ability to grow as both yeasts and molds, depending on their conditions
Dimorphic fungi can be acquired by the ________ of ________ spores from soil. They can cause ________ mycoses.
inhalation
airborne
systemic
Dimorphic fungi that produces white cottony colonies which turn brown with age.
Histoplasma capsulatum
What disease does Histoplasma capsulatum cause?
Histoplasmosis
What is distinctive of Histoplasma capsulatum?
tuberculate macroconidia (large spores with tubercles)
How is Histoplasmosis acquired?
acquired by inhalation of spores from soil heavily contaminated with bird or bat droppings
Histoplasmosis is usually ____-______, but commonly causes ______ of the lungs.
self-limiting
scarring
Why can histoplasmosis present as X-ray diagnostic dilemmas?
Can be a diagnostic dilemma since it leaves scars, esp. if predisposed for lung tumours (e.g. 20 pack year smoking history)
Histoplasmosis can disseminate into the __________ system (liver, spleen, bone marrow) and is the only ____________ fungus.
reticuloendothelial system
intracellular
What is the only intracellular fungus?
Histoplasma capsulatum
Most dangerous and most infectious of all fungi.
Coccidioides immitis
Young colonies appear moist and seem to adhere to agar, but with age, develop a cottony appearance resembling spider webs
Coccidioides immitis
How does Coccidioides immitis grow spores?
Right in the hyphae - arthroconidia (alternating barrel-shaped)
Coccidioidies produces a common infection in the desert areas. What is it?
Commuity-acquire San Joaquin pneumonia (sometimes called valley fever)
Coccidioides immitis can disseminate where?
Bone and CNS (meningitis)
Coccidioides is common where?
SW USA
What are some areas that are SW in the US?
Arizona
This fungi is the major exception to inhalation acquisition.
Sporothrix schenckii
Where do most people get Sporothrix schenckii infection from?
rose thorns
Chronic skin and lymphatic infection which is typically associated with gardening injuries, particularly from rose thorns.
Sporotrichosis
In culture, the conidia of Sporotix is arranged how?
in rosettes
What is the presentation of sporotrichosis on the skin?
Ropy lymphadenopathy
lymph nodes flare up and sometimes ulcerate along the arm
(easy diagnosis)
