Intro to Medical Mycology - Kozel Flashcards
T/F Mammals are intrinsically resistant to fungus infections
true
What mechanism makes mammals resistant to fungus?
Body temp: every 1C above 30C excludes 6% of fungal species
What caused the emergence of fungal pathogens in 50?
introduction of abx’s, HIV, and immunosuppressive therapies
There is a (high/low) probability that we will see new fungal pathogens in the future
high
What strerol is present in fungal cell walls?
ergosterol
What are the two types of glucan bonds in the fungal cell wall?
B1-3 glucan and B1-6 glucan
What is the type of mannan found in fungal cell walls?
saccharomycetes
What is the type of galactomannan found in the fungal cell wall?
Euascomycetes
Where is the chitin found in the fungal cell wall?
right against the plasma membrane
Where are the mannoproteins found in the cell wall?
on the external edge
In what direction do the B 1-3 glucans go?
From the plasma membrane up to the surface of the wall
In what direction do the B1-6 glucans go?
laterally across the surface of the membrane
How does yeast reproduce?`
vegetatively or by budding or by fission
is yeast single or multicellular?
single
(blank) is a String of budding cells marked by constrictions rather than septa at the junctions
pseudohyphae
(blank) are multicellular structures that elongate at tips by apical extension
hyphae
Describe coenocytic hyphae?
hollow, multinucleate hyphae
Septate hyphae are divided by (blank)
partitions or cross-walls
Conidia are asexual reproductive elements (spores) produced by budding at the (blank or blank) of a hypha
tip or side
What asexual reproductive element is produced by fragmentation of hyphae?
Arthroconidia
Which asexual spores are produced inside a containing sack-like structure (sporangium)
Sporangiospores
Describe the following terms regarding sporangiospores: sporangiospores sporangium columella sporangiophore Aseptate hyphae Rhizoides
DANDELION
Sporangiospores are the individual seeds inside the poofy part
Sporangium is the whole big white poofy part
Columella is the bulb where the seeds attach
Sporangiophore is the stem
Aseptate hyphae are lateral stems
Rhizoides are the roots
Coccidioides immitis presents as Arthrocondia, which means it looks like:
square, JOINTED bamboo rods
Aspergillus presents as conidia, which means it looks like;
A peacock feather
Conidia of penicillium is a little different in that it looks like:
more like a fan than a feather
What genera are in the group Mucormycetes? Only 2
Rhizopus and Mucor
Describe the morph of Mucormycetes?
Broad, thin-walled hyphae with multiple nuclei (coenocytic); septae are rare; sporangiospores
Cryptococcus
Malassezia
Trichosporon
belong to what group?
Badiomycetes
What is the morph of:
Cryptococcus
Malassezia
Trichosporon
Budding yeasts, septate hyphae with clamp connections and arthroconidia
Pneumocystis jirovecii has what morph?
Trophic forms and cystlike structures
What is the only genera within the saccharomycetes group?
Candida saccharomycetes
What is the morph of candida saccharomycetes?
Budding yeasts and hyphae, pseudohyphae
Dermatophytes Blastomyces Histoplasma Aspergillus Coccidioides belong to what group?
Euascomycetes
Describe the morph of: Dermatophytes Blastomyces Histoplasma Aspergillus Coccidioides
Budding yeasts, septate hyphae, asexual conidia on specialized structures, and arthroconicia
What is the gold standard for yeast Dx?
culture
How long does it take to culture yeast?
FOR FUCKING EVER; days to weeks
What does culturing yeast allow you to do?
sensitivity testing
T/F: yeast cultures will be neg for a disseminated disease
true
What do you use to digest the tissue for direct scrapings of fungal samples for microscope?
KOH
A negative stain of CSF under direct microscopy is used to view (blank)
encapsulated cryptococci
What are all of the methods of diagnosing fungal infection?
- Culture
- Direct microscopy
- Histopath
- Serology
- Moleuclar methods (PCR)
- Ag detection
T/F: fungal PCR is FDA approved for Dx
false; no FDA cleared molecular methods!
Detection of Abs to fungus for Dx is most useful for what two bugs?
coccidiodomycosis and hhistoplasmosis
Antigen detection is good at picking up CrAg which is shed by:
cryptococcosis
Beta glucan detection detects the glucan in the cell wall and has (blank) sensitivity and specificity
variable
Galactomannan is FDA cleared for the Ag detection Dx of (blank)
Aspergillus
What three other bugs can you detect via galactomannan besides Aspergillosis?
Histoplasmosis, blastomycosis and coccidioidomycosis
Blastomycosis Histoplasmosis Coccidioidomycosis Penicilliosis Are (blank) mycoses
endemic
Aspergillosis Candidiasis Cryptococcosis Mucormycosis Pneumocystosis are (blank) mycoses
Opportunisic
Differentiate between superficial, cutaneous, and subcutaneous mycoses
superficial: superficial surfaces of hair and skin
cutaneous: infects keratinized layers of hair, skin, and nails
subcutaneous: infects deep layers of skin, cornea, muscle, and connective tissue
Pityriasis versicolor – Malassezia furfur Tinea nigra – Hortae werneckii Black piedra – Piedraia hortae White piedra – Trichosporon spp. (are superficial/Q/subQ)
superficial
Dermatophytoses – infections of skin
Tinea unguium – infections of toes
Onychomycosis – infections of nails
(are superficial/Q/subQ)
cutaneous
Hyaline molds – Acremonium spp., Fusarium spp.
Pigmented fungi – Alternaria spp., Cladosporium spp, Exophila spp.
causing Abscess formation, nonhealing ulcers, draining sinus tracts
(are superficial/Q/subQ)
subQ
T/F: superficial mycoses do not cause tissue damage
true
What causes the pathology in the cutaneous mycoses?
the host response
Microsporum spp.
Trichophyton spp.
Epidermophyton floccosum
are causative agents of what type of mycoses?
cutaneous
Do subcutaneous mycoses become disseminated?
nope
saprobic and parasitic phases make up (blank)
dimorphism
WHat bug is endemic to the Ohio and Mississippi river valleys?
Blastomyces dermatidis
Describe the histo of blastomyces in the tissue and saprobic phases??
tissue: broad based yeast
saprobic: nondescript mycelium
What does blastomyces dermatidis cause?
Pulmonary disease, strangely enough
Also extrapulmn in the skin, GU, and CNS
What fungus has the following characteristics:
Tissue – intracellular budding budding yeast
Saprobic phase – tuberculate macroconidia
Histoplasma capsulatum
In what environment (not location) normally find histoplasma capsulatum?
soil with with high nitrogen content–BIRD AND BAT DROPPINGS
Where in the world do you find histoplasma capsulatum?
Ohio and MIssissippi river valleys, Mexico, Central/South America
T/F: most cases of histoplasma are asymptomatic in the actue phase
true
What are the three phases of histoplasma infection?
- actue pulmonary
- chronic pulmonary
- progressive disseminated
What fungus has the following charactersitics:
Tissue – Endosporulating spherule
Saprobic phase – arthroconidia
Coccidioides immitis/posadasii
Where in the world do you find coccidioides?
Southwestern US, Mexico, Central and South America
T/F: Coccidioides and histoplamsa have the same clinical appearance
true
What fungus has the following charactersitics:
Tissue – sausage-shaped yeast
Saprobic phase – pigmented mold
Penicillium marneffei
Where do you find penicillium ecologically?
soil, carried by the bamboo rat
Where in the world do you find penicillium?
SE Asia, think about the bamboo rat!
Disseminated penicillium infection is seen more often in immunocompromised pts with (blank)
AIDS
What fungus has the following charactersitics:
Tissue – large, multiply budding yeast
Saprobic phase - nondescript mold
Paracoccidioides brasiliensis
Where in the world do you find paracoccidioides?
South and Central America
T/F: Paracoccidioides can cause both self limiting and progressive pulmonary disease
true
In what age group is paracoccidioides more common?
children
T/F: Aspergillus is ubiquitous in air, soil, and decaying matter
true
How do you contract Aspergillus?
inhalation of spores
Describe the appearance of Aspergillus?
septate, branching hyphae in tissue
What are some of the disease caused by aspergillus?
Allergic reactions
Obstructive paranasal or bronchial
Invasive pulmonary and disseminated
A neutropenic or immunodeficient pt (solid organ transplant or bone marrow) with Aspergillus will develop (blank)
invasive pulmonary and disseminated disease
What bug has Yeast-like forms with buds, pseudo-hyphae and germ tubes and is NORMAL FLORA of humans?
Candida
The AIDS related candida infection is what?
Esophagitis
What is thrush?
oropharyngeal infection of candida
T/F: you can have candida in the blood
true
What is a lady’s yeast infection?
candida
What bug is an encapsulated yeast that is a ubiquitous saprophyte found in pigeons and trees
cryptococcus neoformans
What are the two species of cryptococcus?
Neoformans and gattii
How do you diagnose C. neoformans?
immunoassay for capsular ag
What are the really scary things that cryptococcus causes?
cryptococcal meningitis
“ “ pulmonary disease
What pt group often gets cryptococcal infections?
AIDS pts
What bug is aseptate (coenocytic) hyphae, ubiquitous in soil and decaying vegetation, and is transmitted by inhalation of spores and causes Rhinocerebral disease unique to diabetic ketoacidosis?
Mucormycosis–both Mucor and Rhizopus
What does Mucor do to your blood vessels?
it is ANGIOINVASIVE
What very specific groups of patients are at risk of Mucor infections (think diabetics KA)
metabolic acidosis and hematologic malignancy
T/F: pneumocystis jerovecii has only an asexual life cycle
false; sexual and asexual
What are the three forms of pneumocystis j?
tropic, sporocyst and cyst
What form of pneumocyst are seen as empty, collapsed balls?
cysts
What is the reservoir for pneumocystis?
humans
T/f: humans have a naturally high resistance to pneumocystis
true
T/F: despite high resistance, most normal people are naturally infected with pneumocystis
true
What histologically named disease does pneumocystis cause?
interstitial plasma cell pneumonitis
What two groups of pts are at high risk for pneumocystis?
AIDS and kids
