Intro to Medical Mycology - Kozel Flashcards by Colt Williams

T/F Mammals are intrinsically resistant to fungus infections

true

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What mechanism makes mammals resistant to fungus?

Body temp: every 1C above 30C excludes 6% of fungal species

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What caused the emergence of fungal pathogens in 50?

introduction of abx’s, HIV, and immunosuppressive therapies

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There is a (high/low) probability that we will see new fungal pathogens in the future

high

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What strerol is present in fungal cell walls?

ergosterol

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What are the two types of glucan bonds in the fungal cell wall?

B1-3 glucan and B1-6 glucan

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What is the type of mannan found in fungal cell walls?

saccharomycetes

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What is the type of galactomannan found in the fungal cell wall?

Euascomycetes

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Where is the chitin found in the fungal cell wall?

right against the plasma membrane

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Where are the mannoproteins found in the cell wall?

on the external edge

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In what direction do the B 1-3 glucans go?

From the plasma membrane up to the surface of the wall

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In what direction do the B1-6 glucans go?

laterally across the surface of the membrane

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How does yeast reproduce?`

vegetatively or by budding or by fission

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is yeast single or multicellular?

single

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(blank) is a String of budding cells marked by constrictions rather than septa at the junctions

pseudohyphae

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(blank) are multicellular structures that elongate at tips by apical extension

hyphae

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Describe coenocytic hyphae?

hollow, multinucleate hyphae

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Septate hyphae are divided by (blank)

partitions or cross-walls

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Conidia are asexual reproductive elements (spores) produced by budding at the (blank or blank) of a hypha

tip or side

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What asexual reproductive element is produced by fragmentation of hyphae?

Arthroconidia

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Which asexual spores are produced inside a containing sack-like structure (sporangium)

Sporangiospores

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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

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Coccidioides immitis presents as Arthrocondia, which means it looks like:

square, JOINTED bamboo rods

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Aspergillus presents as conidia, which means it looks like;

A peacock feather

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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?

1. Culture 2. Direct microscopy 3. Histopath 4. Serology 5. Moleuclar methods (PCR) 6. 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?

1. actue pulmonary 2. chronic pulmonary 3. 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