Test 3: Other Fungal Infections (Mycoses) Flashcards
What fungi are hyphal molds and mostly respiratory infections?
- aspergillus
- mucor (zygomycetes)
What fungi are dimorphic fungi and mostly respiratory infections?
- histoplasma
- blastomyces
- coccidioides
What fungi are yeast?
- cryptococcus
What fungi are hyphal molds?
- dermatophytes
What is the morphology of aspergillus?
- filamentous mold with hyphal filaments
- septet hyphae (cross-walls)
- extensive hyphal branching (45 degrees) with acute angles
What is the reproduction of aspergillum?
- airborne release of spores from hyphae into air and can be inhaled
What is the habitat of aspergillus?
- outdoor (organic matter) and indoors (damp/wet surfaces)
What is the transmission of aspergillus?
- inhalation of airborne asexual spores
What is the dx for aspergillus?
Direct Microscopic Examination by:
- silver stain to see 45 degree branching and septet hyphae
What is the tx for aspergillus?
- key tx: voriconazole
- CAN NOT BE MISTKAEN FOR MUCOR or proliferate mucor
What is the prevention for aspergillus?
- no vaccine
- protect pt from spores via HEPA filtered rooms in hospital settings
What does aspergillus lead to?
generally a respiratory disease but can give oral manifestations
What is the big difference between mucor and aspergillus?
- mucor are HIGHLY invasive
- mucor invade major bvs leading to black skin or pus (necrotic tissue)
- mucor pathogen: rhizopus
What is the morphology of mucor?
- non-septate hyphae
- 90 degree branching
What is the reproduction of mucor?
- same as aspergillus in that is releases spores into air
What is the habitat of mucor?
- same as aspergillus in that it is outdoors and indoors
What is the transmission of mucor?
- same as aspergillus in that the spores are inhaled
- also spore implantation into tissue via trauma
Who is at risk of developing mucor infection?
- uncontrolled diabetes
-ketoacidosis - cancer, neutropenic
What is the dx for mucor?
Direct Microscopic Examination by:
- silver stain to see 90 degree branching and nonseptate hyphae
Sab’s Agar
What is the tx for mucor?
- aggressive surgical measures to get rid of affected tissue- ESSENTIAL
- aggressive correction of underlying condition
- aggressive anti-fungal therapy
What do we always avoid to give a mucor infection?
Voriconazole because it enhances virulence of major
What do we need to know about histo, blasto, and coccidio?
- oral manifestations are rare but seen in immunocompromised
- all dimorphic
- histo and blasto will present as yeast
- coccidiodes will present as a spherule
What is the habitat for histo, blasto, and coccidio?
- histo= bird, bat dropping
- blasto= organic matter, rotting/decaying/plant/animal droppings
- coccido= fine sand and silt (southwest/desert)
What is the dx of histo, blasto, and coccidio?
- silver stain
- 10% KOH to observe yeast or spherules
What is the morphology of cryptococcus?
- yeast that produces a polysaccharide capsule
How is cryptococcus spread?
- through inhalation of yeasts from exposure to pigeon droppings
What is the dx of cryptococcus?
- stain with India ink to view the capsule
T/F: Dermatophytes have no oral manifestions
True!
but can be expressed on facial surface
What are dermatophyte infections termed as?
“tinea”
What are the 3 primary infections caused by dermatophytes?
- trichophyton
- microscporum
- epidermophyton
What is the key virulence factor for dermatophytes?
- secrete keratinase (degrade keratin in hair, skin, and nails)
T/F: dermatophytes are only in immunocompromised patients
False!
This is the only fungi infection we discuss that does not have to be in immunocompromised patients. ex: athletes foot
How do we distinguish epidermophyton?
- club-shaped macroconidia
- no microconidia
How do we distinguish microsporum?
- spindle-shaped macrocondidia AND microcondidia
How do we distinguish trichophyton?
- cigar-shaped some macrocondidia but MOSTLY microcondidia
Tinea capitis:
- scalp hair/skin
Tinea faciei:
- face
Tinea barbae:
- beard, mustache, neck
Tinea corporis:
- trunk, arms, legs
Tinea manuum:
- palms of hands
Tinea cruris:
- groin
Tinea pedis:
- feet (soles, between toes)
Tinea unguium:
- nails (onychomucosis)
What is the dx of
What is the dx of dermatophytes?
10% KOH