Final Test Flashcards
What is a fungus?
Is is a nucleated, spore bearing; cell walls of chitin or cellulose, reproduce sexually or asexually, includes both molds and yeasts.
What are mycoses?
Infections caused by fungi, cutaneous, subcutaneous, systemic, opportunistic.
What is a mould?
fungus composed of filaments that generally form a colony that may be either filamentous, powdery, woolly, or smooth.
What is a yeast?
a unicellular budding fungus that usually produces a soft, pasty, smooth colony; usually no filamentous growth can be observed macroscopically.
What is the growth rate for Yeasts?
24-72 hours
What is the growth rate for moulds?
3-5 days, 10 days-2 weeks, or some up to 4 weeks.
What is the most commonly isolated yeast?
Candida albicans
Cryptococcus neoformans
Associated with fowl excreta, meningitis especially in AIDS patients.
What is hyphae?
Hyphae are tubular structures of fungus. Many together are mycelium.
What is a conidia?
A conidia is an asexual structure born on the side or end of hyphae or conidiophores. They may be single celled or contain multiple cells.
What is an arthroconidia?
asexual spores formed with hyphae break up at the points of septation.
What is a vesicle?
It is an enlarged structure at the end of a conidiophore.
What is a sporangium?
a closed saclike structure in which asexual spores are formed.
What are rhizoids?
Root like structures
Rhizopus
Found in decaying vegetation, can cause life-threatening illness in immunocompromised, spores enter in through nasal passageway.
Aspergillus fumigatus
Found in the environment, most common fungal contaminant in the lab, causes respiratory disease.
What are DERMatophytes?
moulds that infect the superficial layers of skin and can be transmitted from human host to human host.
What is tinea unguium?
Infection of the nails
What is a dimorphic mould?
It is a fungus that has the propensity to present itself in two different forms: as a mold at room temperature to slightly elevated temperatures, and as a yeast above 37 deg C.
Blastomyces dermatitidis
Endemic in Mississippi, Missouri, Ohio river valley. Primarily infects the skin, bone, and the lungs.
Coccidioidis immitis
Found in dry, arid areas. Respiratory infection that resolves rapidly.
Histoplasma capsulatum
Cave disease, associated with fowl excreta (chickens, bats, pigeons.) Most cases are asymptomatic but it does affect the lungs.
Sporothrix schenkii
Prick your finger on a plant’s thorn or get a sliver. Associated with decaying plants.
What is transient bacteremia?
It lasts minutes to hours. Dental (90%), GU, and GI procedures (each 50%). May be initial manifestation of focal infection such as pneumonia, osteomyelitis, meningitis, arthritis.
What is intermittent bacteremia?
Periodic seeding from undrained or inadequately treated focus.
What is continuous bacteremia?
Intravascular infection such as endocarditis, vascular access infection, septic thrombophlebitis.
For intermittent bacteria when does the highest yield occur?
in the 2 hours preceding clinical symptoms
For most infections how many blood cultures should be drawn?
2 blood cultures. For possible endocarditis draw 3 blood cultures separated in time by at least 30 minutes.