Exam I Study Guide Flashcards by Alex Olsen

Are fungi classified as eukaryotic or prokaryotic?

eukaryotic

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What is the structural element that comprises a fungus?

hyphae

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Which class of fungi has non-septate mycelium?

zygomycetes

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Why are certain fungi classified as “Fungi Imperfecti”?

They do not exhibit sexual reproduction, sexual phase is undiscovered; Deuteromycetes

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How does the function of reproductive mycelia differ from that of vegetative mycelia?

Vegetative grows below the surface of the medium and anchor the fungus; digestive enzymes
Reproductive projects above the surface of the medium where reproductive structures are located-spores

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To which class do most pathogenic fungi belong?

Deuteromycetes

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What term best describes the nutritional characteristics of fungi?

Heterotrophic/Saprotrophic

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Are fungi aerobi or anaerobic?

aerobic

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What is the best medium for the primary isolation of fungi?

Sabourad’s (w/ dextrose)

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What is the purpose of corn meal agar?

nutritionally deprives the organism so it will sporlate

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How long should routine fungal cultures be held before being discarded?

4 weeks

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What three things does the counting medium lactophenol cotton blue do?

lactic acid-preserves fungal structures
phenol-reduces contamination of the environment
cotton blue-stains hyaline fungal structures

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When a systemic mycosis has spread to various organs, what term is used to describe it?

disseminated

systemic

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What organism is best described as a thick-walled yeast cell with buds attached by a broad base?

Blastomyces dermatitidis

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Which systemic fungus is always a yeast?

Cryptococcus

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How is histoplasmosis acquired?

inhalation of spores from free-living fungus; infect reticuloendothelial system(RES)

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Name five species of dimorphic(diphasic) fungi.

Blastomyces
Histoplasma
Paracoccidiodes
Sporotrichosis 
Coccidiodes

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Which systemic fungus produces thick-walled yeast cells with multiple buds in tissue?

Paracoccidiodes braziliensis

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Which fungus can be observed as a non-budding, thick-walled spherule containing endospores in a direct smear from the body?

Coccidiodes imitis

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Which fungus produces spiny, tuberculate macroconidia when cultured, but in the body can be seen as intracellular, yeast-like cells with a large vacuole in the cells of the RE system?

Histoplasma capsulatum

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Cryptococcosis is usually seen as a disease of which body system?

pulmonary

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Which systemic fungus is most fastidious(difficult to grow) in the lab?

Histoplasma

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What systemic fungus causes San Jaquian Valley Fever?

Coccidiodes

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Which systemic fungus causes South American blastomyces?

Paracoccidiodes

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Which stain is best to use to demonstrate Cyrptococcus neoformans in CSF?

India Ink

Which systemic fungus is endemic in Piedmont, NC and can produce a primary pulmonary infection or a primary skin infection which resembles ringworm?

Blastomyces

Which systemic fungus produces chains of arthrospores and can be confused with the saprophytic fungus Geotrichum candidum?

Coccidiodes imitis

What is the macroscopic appearance of Sporothrix scheneckii at 37degrees?

yeast phase: soft, smooth, white to cream color, tan colonies

Phialophora Fonsecaea Cladosporium

Dematiaceous fungi

Which subcutaneous infection produces yeast-like brown cells in clusters in the body?

Chromomycosis

What is the most common cause of maduromycosis? | What color are the granules that are frequently found in the pus?

Petriellidum boydii | yellow to whitish

What fungus produces tear-shaped conidia arranged in rosettes at 25 degrees and yeast cells at 37 degress, and cause a disease common among gardeners know as "rose fever"?

Sporothrix scheneckii

Cladosporium carrionii Phialophora verucosa Fonsecaea pedrosoi Fonsecaeo compacta

Cause Chromomycosis

Which organisms can cause mycetomas(fungal tumors)?

Allechria Boydii Madurella mycetomatis Petrielldieum

An organism which produces brown, branching septate hyphae would be classified as what type of fungus?

Dematiaceous fungi

Fungus infecting the dermis, keratinized areas of the body such as hair, skin and nails

Dermatophytes

What device can be used as an aid to select hairs infected with ringworm?

Wood's Light | UV light

What type of hair infection is characterized by empty areas or tunnels where the hyphae have degenerated visible throughout the entire length of the hair?

Favic

What combination of fungal media would be best to use to culture the dermatophytes?

SabsC and Myosel (acid pH)

Which three genera of fungi all cause true ringworm of the skin?

Microsporum Trichophyton Epidermophyton

What fungus appears velvety white on the front and mahogany on the reverse and will NOT grow on sterile unfortified rice grains?

Microsporum audouinii

What fungus is the most common cause of ringworm in dogs and cats and is characterized by a canary yellow reverse and spiny, spindle-shaped macroconidia?

Microsporum canis

What fungus is most frequently isolated from human ringworm infections and has a deep red reverse pigmentation?

Trichophyton rubrum

What structures are frequently observed in Trichophyton cultures?

spiraled/coiled hyphae nodular bodies racket hyphae

As a rule, which dermatophyte does NOT infect nails?

Microsporum audouinii

Which dermatophyte is the most common cause of epidemic scalp ringworm in American school children?

Trichophyton tonsurans

What fungus cause tinea versicolor?

Malassezia furfur | Pityrosporon furfur

What fungus is the most common cause of tinea cruris?

Epidermatophyton floccosum

What term is used to refer to ringworm of the skin?

tinea corporis

What dermatophyte gives a positive in vitro hair test?

Trichophyton mentagrophytes

Which dermatophyte produces sterile, antler-like hyphae referred to as favic chandliers and causes severe type of ringworm of the scalp called favus?

Trichophyton schoenleinii

Which dermatophyte does not invade the hair and produces oval, smooth walled club-shaped macroconidia and NO microconidia?

Epidermophyton floccosum

Which dermatophyte is the most common cause of ringworm of cattle and requires both inositol and thiamine to grow well?

Trichophyton verrucosum

How is Candida albicans identified?

germ tube test | confirmation of chlamydospore production on corn meal agar

Which fungus is the most common and troublesome laboratory contaminant and is the most pathogenic of the opportunistic fungi?

Aspergillis

If an autopsy revealed systemic infection by fungus with broad, branching non-septate hyphae, which species of fungus could be a likely cause of death?

Mucor/rhizopus

Which fungus commonly produces oval budding cells with pseudohyphae and will produce chlamydospores on cornmeal agar?

Candida albicans

Brown gritty deposits in a sputum specimen are indicative of what genus?

Aspergillis

What clinical conditions can be caused by Candida albicans?

thrush, foamy diarrhea, monilia, type of pneumonia, endocarditis, mycotic keratitis, endopthalmitis

Which species of opportunistic fungi can be causative agents of eye infections?

Altenaria Curvularia Fusarium

``` Which species of Rickettsia causes epidemic typhus? Scrub typhus? Q fever? Rickettsial pox? RMSF? ```

``` Prowazekii R. tsutsugamuschi coxiella burnetti R. akari R. ricketssi ```

How do Rickettsia and Chlamydia differ?

Chlamydia is smaller, they are not dependent on arthropod vectors for their transmission; are more spherical

What clinical conditions can be caused by Chlamydia trachomatis?

inclusion conjungtivitis trachcoma NGU

How is psittacosis spread to humans?

birds; aerosol inhalation

How are Rickettsial infections diagnosed in the laboratory?

Giemsa stain | Weil-Felix reaction

What causes the rash that is frequently observed in Rickettsial infections?

invasion of endothelial cells of blood vessels

What are the characteristics of viruses?

obligateintracellular parasites composed of protein and nucleic acid; RNA or DNA not both seen with electron microscope doesn't respond to antibiotics

What term is used to refer to the viral nucleic acid core together with its protein coat?

nucleocapsid

What is the order of events in the process of viral infection?

``` adsorption penetration viropexis(engulfed) replication assembly release ```

What is interferon?

*prevents viral replication protein produced by cells that are already infected with a virus that protects adjacent, non-infected cells

Which virus produces an acute respiratory infection and is commonly found in increased incidence in military camps?

Adenoviruses

Which virus is the causative agent of the common cold?

Rhinovirus

Which type of virus is referred to as "virus in search of a disease"?

ECHO | enteric cytopathogenic human orpahn

Negri bodies are characteristics of which virus?

Rhapdovirus-rabies

Which virus causes chicken pox?

Varicella-Zoster

With what clinical conditions is EBV associated?

infectious mono | Burkitt's lymphoma

Which virus produces large, red intranuclear inclusions?

CMV-cytomegalovirus

How is Hepatitis A transmitted?

fecal-oral route

Herpes-Zoster(shingles) occurs in patients who have a history of what other viral infection?

Varicella-Zoster -chicken pox

What are the characteristics of Hep B?

serum hep - transmitted by blood | blood contact by IV users, drug addicts

How many serotypes of polio virus are there?

Which vaccines have been developed against polio?

Salk | Sabin

Which virus has been associated with cancer of the cervix and causes genital lesions in humans?

HSV-2

Which fungus is most frequently isolated in the clinical laboratory?

Candida albicans

The _____ test is a serological test used in the identification of Rickettsia that employs three antigens of the bacteria ____ that cross-react with rickettsial antigens.

Weil-Felix reaction | Proteus vulgaris

What virus is associateed with severe congenital abnormalities in the fetus if the mother becomes infected during her first trimester?

Rubella- german measles

What "emerging" viral pathogen causes an upper respiratory tract infection in infants and young children?

RSV - respiratory syncytial virus

To what group of viruses does HIV belong? | These viruses have no DNA and possess what enzyme that is capable of converting RNA to DNA?

Retrovirus | reverse transcriptase

Name two disease processes that are common in HIV patients that are rarely seen in "normal" individuals.

Cryptosporidium CMV toxiplasmosis

prowazekii (epidemic typhus) vector

body louse

tsutsugamuschi (Scrub typhus) vector

larvae mite

akari (rickettsial pox) vector

mite

coxiella burnetti (Q fever) vector

no vector

rickettsi (RMSF) vector

wood tick

Exam I Study Guide Flashcards

(94 cards)