MYCOVIRO - CH 59 Book Flashcards
Except for disease caused by ___, humans are resistant to infections caused by fungi.
dimorphic fungi
Classification of Fungi based on Appearance of Colonies
moist, creamy, opaque, pasty colonies
yeasts
Classification of Fungi based on Appearance of Colonies
– fluffy, cottony, woolly or powdery colonies
Mold or Filamentous fungi
– exhibit either a yeast and filamentous forms
Dimorphic fungi
– when dimorphism is temperature dependent
Thermally dimorphic fungi
Thermally dimorphic fungi produce a mold form at what temp
25C – 30C
Thermally dimorphic fungi produce yeast form at what C
35-37C
– fungi that have more than one independent form or spore stage; not temperature dependent
Polymorphic fungi
4 Phyla
-includes organisms that produce sparsely septate hyphae
Zygomycota
Zygomycota
- asexual reproduction by ?
- sexual reproduction by ?
sporangiospores
zygospores
what phyla
ex. are Rhizopus, Mucor, Rhizomucor, Absidia, Cunninghamella
Zygomycota
what phyla
filamentous
produce true septate hyphae
ascomycota
asexual repro of ascomycota
conidia formation
sexual repro
ascopore
2 forms of ascomycota
teleomorph and anamorph
what phyla is ubiquitous in nature
ascomycota
– fungi that have different asexual forms of the same fungus
*Synanomorphs
sexual reproduction of basidiomycota
basidiopores
plant pathogens; rarely cause disease in humans
basidiomycota
-includes the smuts, rusts mushrooms, Cryptococcus neoformans complex
basidiomycota
– teleomorphic form of Cryptococcus neoformans
*Filobasidiella neoformans
– lack a sexual reproductive cycle
-asexual reproduction through conidia
- Deuteromycota
also called fungi imperfecti
Deuteromycota
dimorphic fungus; has not been assigned to any phylum so it is placed in the order Incertae sedis
Blastomyces dermatitidis –
in which order is Blastomyces dermatitidis assigned
Incertae sedis
classification of fungi based on type of infection
superficial or cutaneous
deep or systemic
subcutaneous
opportunistic
-involve the hair, skin, or nails without direct invasion of deeper tissue
superficial or cutaneous
mycoses which all infect keratinized tissues
superficial or cutaneous
– causes infection to the subcutaneous tissue only (no dissemination to other sites)
Subcutaneous mycoses
examples are Chronomoblastomycosis, mycetoma, phaeohyphomycotic cysts
Subcutaneous mycoses
most common opportunistic mycoses
- Aspergillus
- Candida
- Cryptococcus
– may cause deeply invasive phaeohyphomycoses (produce brown-pigmented structures)
*Dematiaceous fungi
type of pathogen which occurs in immunocompromised host
-not always as virulent, may lead to subclinical disease
primary
type of pathogen, almost any fungus present in the environment
opportunistic
virulence factors (4)
- Size (should be small to reach alveoli)
- Ability to grow at 37C and neutral pH
- Conversion of dimorphic fungi from mycelial form to corresponding yeast or spherule form in the host
- Toxin production
Many fungi have a primary focus in the lungs, thus ___ are almost always included among specimens selected for culture.
respiratory secretions
antifungal agent
- prevents overgrowth by rapidly growing molds
- should be included in at least one of the culture media
cycloheximide
amount of RT secretions for inoculation
0.5 ml
CSF must be filtered through a __ um membrane filter attached to a sterile syringe
0.45 um
CSF Specimen
If
1-drop aliquots
CSF
Media should have no ____
antibacterial or antifungal agents
if CSF processing is delayed, w
- keep at room temperature
* or place in a 30C incubator
Automated blood culture systems (3)
- BACTEC
- BacT/ALERT
- VersaTREK
lysis-centrifugation system
- for dimorphic fungi from blood
- optimal for H. capsulatum recovery and other filamentous fungi
ISOLATOR
Isolator is optimal for ____ recovery and other filamentous fungi
H. capsulatum
temp and incubation time for blood specime
optimal temperature: 30C and incubation time: 21 days
-submitted for dermatophyte culture
Hair, Skin, Nail Scrapings
hair, skin, nail obtained by
scraping
hair, skin, nail obtained by scraping using
scalpel blade or microscope slide
mycosel agar contains
cycloheximide and chloramphenicol
