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Infectious Disease EXAM 3 - Santanello Fungal
Infectious Disease EXAM 3 - Santanello Fungal
32
Pharmacology
Graduate
02/03/2011

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Term
eukaryotic
Definition
are fungi eukaryotic or prokaryotic?
Term
budding or division
Definition
how do yeasts reproduce?
Term
multicellular, branching filamentous hyphae forms
unicellular yeasts
Definition
types of fungal morphology
Term
mycelium
Definition
in the filamentous forms of a fungus, a mass of hyphae is called a ( )
Term
asexual reproduction results in spores formed by hyphae
sexular spores are less common
Definition
how do filamentous fungi reproduce?
Term
like bacteria, fungi absorb nutrients rather than ingesting them like animals
fungi grow best in pH ~5, this is too acidic for most bacteria
fungi can grow on low moisture substances unlike most bacteria
fungi require less nitrogen than bacteria
Definition
similarities and differences between bacteria and fungi
Term
most yeasts are facultative anaerobes
most molds are aerobes
Definition
respiration of yeasts and molds
Term
fungal cell walls are similar architecturally to plants but not chemically; fungal cells walls are rigid
there are 3 layers of polysaccharides (glucans and glycoproteins)
also chitin and mannans are significant components of certain cell walls
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ergosterol and zymosterol instead of cholesterol for the main sterol components of the cell membrane
Definition
structure of fungal cell walls
Term
they lack peptidoglycan
Definition
why are fungal cell walls not susceptible to antibiotics?
Term
saprophyte
most infections are caused by saprophytic fungi
Definition
an organism that grows on and derives its nourishment from dead or decaying organic matter
Term
inhalation
ingestion
direct skin contact
Definition
how are fungal infections acquired?
Term
low pH
fatty acids
turnover of skin
IgA at mucosal surfaces may limit growth
Definition
what defenses prevent fungal colonization in the human body?
Term
1) hypersensitivity to fungal antigens
2) production of mycotoxins (exotoxins)
3) mycoses - growth of a fungus on or in the body
Definition
through what 3 mechanisms do fungi cause disease?
Term
superficial
Definition
what type of mycoses?
affects body surface (skin, hair, nails)
ex) dermatophytosis (ringworm) affects outermost keratinized tissues of the hair, nails, and stratum corneum of skin
Term
subcutaneous
Definition
what type of mycoses?
confined to the dermis, subcutaneous tissue or adjacent structures
ex) rare and confined to tropical regions of the world; usually result from inoculation of saprophytic fungi from soil into subcutaneous tissue (via a thorn, insect bite, fist spine)
Term
systemic mycoses
Definition
what type of mycoses?
affects internal organs, systems
may result from inhalation of air borne spores, ingestion, or IV lines
ex) Histoplasmosis, Aspergillosis
Term
primary pathogenic fungi
Definition
infection occurs in previously healthy persons and arises through a respiratory route
type of systemic mycoses
Term
opportunistic fungi
Definition
cause disease in immune compromised hosts
type of systemic mycoses
endogenous example = candida
exogenous example = aspergillosis
Term
dermatophytes
Definition
infections of skin, hair, nails, and outer layers of epidermis
secrete keratinase, an enzyme that degrades keratin
ex) athlete's foot: may be an infection caused by several different fungi, including yeasts
Term
dimorphic fungi
Definition
capable of changing from a multicellular mold form in nature to a budding single celled form when causing infection
many pathogenic species
ex) Histoplasmosis capsulatum
Term
Histoplasmosis
Definition
caused by Histoplasma capsulatum
cause disease by inhalation (lung infection often mild)
bird feces provide nutrients (nitrogen) for the fungus
upon inhalation, small budding forms phagocytosed; infections of macrophages and histiocytes (fixed macrophages)
transient spread leads to flu like symptoms
hepatosplenomegaly in immunocompromised patients
Term
Coccidioidomycosis
Definition
Coccidioides immitis is the pathogen
spores found in dry soils of the Southwestern US, Central America, and South America
highly infective in dusts in endemic areas
like Histoplasmosis, may be asymptomatic; may present as flu-like illness, similar to TB
hyphal growth from lung aspirate
small percentage (~1%) of patients develop a pustular skin rash or dissemination to the bones or meinges
Term
Aspergillosis
Definition
caused by Aspergillus species: A. fumigatus, A. niger, A. flavus
dangerous in immunocompromised patients
Aspergillus spores are nearly everywhere
A. fumigatus causes severe allergies
in the lung (aspergilloma) may be contained, but if it becomes systemic has a high mortality
Aspergillus flavus (from peanuts and grains) produces aflatoxin that has mutagenic effects on the liver
Term
Cryptococcosis
Definition
caused by Filobasidiella neoformans
encapsulated yeast that is inhaled
leads to meningoencephalitis
may also involve skin, UT, eyes, lungs, bones, joints, myocardium, prostate gland
Term
Pneumocystis
Definition
caused by Pneumocystis jiroveci
opportunistic infection of elderly, premature babies, immune compromised
lung tissue infected filling the alveoli with fluid
always thought to be protozoan until recently
Term
yeasts
Definition
nonfilamentous, unicellular fungi; typically oval or spherical
like molds, found almost everywhere
Term
a number of different stains can be used to detect and characterize fungi
Gram staining can be used in certain species
Definition
laboratory diagnosis of fungal diseases
Term
Histoplasmosis capsulatum
Definition
pathogen that causes Histoplasmosis
Term
Coccidioides immitis
Definition
pathogen that causes Coccidioidomycosis
Term
Aspergillus fumigatus
Aspergillus niger
Aspergillus flavus
Definition
Pathogens that cause Aspergillosis
Term
Filobasidiella neoformans
Definition
pathogen that causes Cryptococcosis
Term
Pneumocystis jiroveci
Definition
pathogen that causes Pneumocytsis
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