Final Flashcards
Dematiaceous fungi general characteristic
mostly contaminants except for ICP
reverse of colony is usually jet black
dark colored molds
relatively fast growth
dematiaceous fungi list of organsims
Aureobasidium sp. Alternaria sp. Curvularia sp. Stemphylium sp. Ulocladium sp.
Alternaria sp macro
3-5 days growth
cottony consistency w/ black color & a light border
reverse is black
Alternaria sp. micro
chains of muriform club-shaped (DRUM STICK) macroconidia (!)
Curvularia sp. macro
3-5 days growth
colony is green to brown w/ wooly consistency
Curvularia sp. micro
conidiophores are bent w/ multi-celled macroconidia w/ BOOMERANG shapes- due to the overgrowth of the center cells
divided by transverse septa
Cladophialophora carionii
most commonly associated w/ cerebral abscesses
cladophialophora carionii growth characteristics
10-14 days
cottony to velvety consistency
green to brown to black color
most strains do not grow well in temps > 37C
cladophialophora carionii microscopic characteristics
long, straight or branched chains of ellipical or lemon-shaped conidia borne from either tips of flask-shaped phialides or from the tips of the hyphae
fusiform shape w/ slightly pointed tips
dark disjuncture between conidia
Fonsescae pedrosoi
most common cause of superficial fungal chromomycosis
fonsecaea pedrosoi growth characteristics
12-14 growth
small colonies & button-like
colors : brown to olive to black
fonescaea pedrosoi microscopic
short phialides give rise to single or short chains of elliptical conidia
2 types of sporulation:
fonsecaea (acrotheca) & rhinocladiella
Phialophora verrucosum
found to cause chromomycosis
phialophora verrucosum growth
7-20 days
wooly, cottony or velvety consistency
olive green, brown, or black
black reverse
phiaophora verrucosum microscopic
short, flask or VASE-SHAPED PHIALIDES
thin-walled, dark staining, elliptical conidia terminate in a popbottle-shaped collarette
philalophora sporulation
produced laterally from the hyphae
short, urn-shaped & produce ball like aggregates of spherical, dark conidia from cup-shaped collarettes
phialophora (exophiala) sporulation
long & tapered phialides
from the tips of collarettes, elliptical-shaped conidia from loose clusters or fall along the sides of the phialide
Cladosporium sporulation
straight or branching phialides produce chains of dark-staining, elliptical conidia that are attached by a dark staining scar or dysjunctor
Acdrotheca sporulation
short, straight or branched phialides are produced sympodially from the hyphae producing short chains of elliptical conidia
rhinocladiella sporulation
dark-staining, elliptical conidia attached by short, hair-like denticles are producued laterally & on either side of straight phialides
mycetoma
chronic, purulent infection of the subcutaneous tissue
usually on the foot or hands often extending into the underlying fascia, periosteum & bone
Chromomycosis
lesions appear initially @ sites of trauma or a penetrating puncture wound
can have satellitte lesions & varigated coloration
Dimorphic fungi general characteristics
colonies are generally slow growing (5-15 days)
@30C colonies have cobweb mycelium & focal areas of yeast conversion may be seen
relatively more pathogenic
Blastomyces dermatitidis yeast
8-15 um thick walled yeast cells w/ a single broad based bun
7-10 days @35C
blastomyces dermatitidis mold
ropelike septate hyphae w/ single-celled conidia @ tip of single conidiophore (LOLLIPOPS)
cobweb appearance of colonies
coccidioides immitis yeast
NO LABORATORY YEAST FORM
forms spherules w/ endospores in tissues
coccidioides immitis mold
barrel-shaped arthroconidia (!) separated by empty staining spacess
colonies are usually gray-white w/ cobweb consistency
Histoplasma capsulatum
major pathogen of dimorphic fungi
histoplasma capsulatum yeast
small w/ yellow hue
pseudocapsules seen in tissues
reproduction is by polar buds w/ daughter cells connected by a narrow isthmus
histoplasma capsulatum mold
large TUBERCULATE, MACROCONIDIA w/ few microconidia
10-14 growth
white cobweb colonies
Sporothrix schenckii yeast
single budding, elongated ‘CIGAR-BODIES’ blastoconidia (!)
growth may be rapid
initially cream white & darken w/ age ‘black yeast’
sporothrix schenckii mold
oval conidia borne in a daisy head pattern from straight, tapered conidiophore ‘rosette’/’sleeve’ arrangement
PICTURE ID
Paracoccidioides brasiliensis yeast
thick-walled yeast cells w/ multiple elongated, elliptical daughter buds ‘MARINER’S WHEEL’
VERY LARGE- do not confuse w/ histoplasma
gray or white colonies that become yellow/brown & wrinkled w/ age
paracoccidioides brasiliensis mold
single clavate microconidia borne singly from short conidiophores (LOLLIPOPS) septate & branched hyphae w/ terminal chlamydospores
histoplasma capsulatum endemic area & infection
ohio, mississippi river valley drainage
FOUND IN STARLING ROOSTS
pulmonary infection
Sporothrix schenckii endemic area & infection
world-wide in decaying vegetative matter in temperate & tropical regions
found in sphagnum moss - rose handlers
puncturing the skin/cutaneous infection
‘rose gardeners disease’
paracoccidioides immitis endemic area & infection site
central & south america
lungs
Coccidioides immitis endemic area & infection site
south west US, SanJuakeen valley, mexico, central & south america
lungs - coccidioidomycosis
blastomyces dermatitidis endemic area & infection site
southeast & ohio & mississippi river valleys & wisconsin & minnesota
moist soil & rotting leaves
lungs, cutaneous, disseminated, genitourinary
4 ways to differentiate between diphasic molds & contaminants
- rate of growth
- growth on media that contains cyclohexamine
- presence of cobweb white mycelium
- yeast form
Candida albicans
pseudohyphae (!)
reproduce via blastoconidia (!)
form thick-walled chlamydospores !!
germ tube positive!
candida tropicalis
pseudohyphae w/ blastoconidia
torulopsis glabrata
no pseudohyphae
cryptococcus neoformans
ENCAPSULATED YEAST
pseudohyphae are rarely seen (!)
distinctive brown color on bird seed agar due to production of phenoloxidase
candida parapsilosis
pseudohyphae
giant cells
rhodotorula
RED-PINK COLONY!
urease positive
AIDs patients
Geotrichum
rectangle shaped arthroconidia (!)
‘hockey sticks’
produce germ tubes (look VERY different from candida albicans)
tricosporon beigelii
waxy looking colony
produce blastoconidia - looks like rabbit ears
urease positive
malassezia furfur
pityriasis versicolor
NEEDS TO BE GROWN IN THE PRESENCE OF LIPIDS- agar surface is coated in olive oil
usually seen in skin scrapings as opposed to culture
‘spaghetti & meatballs’
sacchromyces cerevisiae
budding blastoconidia mixed w/ small spherical acid-fast staining ascospores
beer yeast
candida ablicans clinical manifestation
everything- cutaneous, thrush, colitis, pulmonary, cystitis
endocarditis
disseminated
candida tropicalis clinical manifestation
usually nonpathogenic
ICP
torulopsis glabrata clinical manifestation
primary pathogen in the urinary tract
cryptococcus neoformans clinical manifestation
meningits
respiratory issues
can lead to progressive fibrosis & cutaneous issues
ocular & disseminated
candida parapsilosis clinical manifestation
endocarditis
bone marrow transplants
3 laboratory tests that aid in the ID of yeasts
- germ tube test - diagnostic for candida albicans
- CHO assimilation test
- ascospore formation - saccromyceses
3 lab tests that aid in the ID of cryptococcus
- caffeic acid ferric citrate test - positive for crypto
- niger seed (bird seed) agar- brown for crypto bc of phenoloxylate enzyme
- urease test - crypto is positive
virus structure
DNA or RNA
capsid - protein coat
nucleocapsid - genome & its protein coat together
envelope
steps of viral infection
absorption/attachment penetration uncoating replication & translation assembly & maturation release/egress - lysis if naked virus & budding if enveloped
collection for virus specimen
right before & at onset of symptoms
collect within 3 days of symptoms
aspirated secretions
swabs - no calicum aglinate
sample processing
best cultured immediately
refrigerate if necessary @ 4C
freeze only if longer than 4 days & only at -70C
3 major methods of diagnosis
- direct detection of virus in clinical specimen
- isolation of the virus in cell culture
- serologic assays to detect viral antibodies
viral transport medium
buffered isotonioc solution w/ a protein (albumin, gelatin or serum) to protect less stable viruses; sometimes w/ antibiotics to inhibit contamination
samples should be kept moist
direct detection of virus
cytopathic effect (CPE) from cell scrapins - brightfield light microscopy
direct fluorescent antibody (DFA) staining
enzyme immunoassays
nucleic acid-based assays
