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30 Cards in this Set

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What is Pseudomonas?
Oxidase-positive, pigment-producing, encapsulated rods with polar flagella.
What are the oxygen requirements of Pseudomonas?
Obligate aerobe
What is a specific metabolic characteristic of Pseudomonas?
Unable to ferment carbohydrates, including glucose.
Where is Pseudomonas found?
Soil, plants, and water (including humidifiers, ventilators, adn tap water)
Where is the main pathogen of the Pseudomonas family?
P. aeruginosa
How is it transmitted?
Water aerosols, aspiration, or fecal contamination
What parts of the body does it colonize?
Skin
Upper respiratory tract
Colon
Which group of patients is at increased risk for P. aeruginosa infection?
Hospitalized patients P. aeruginosa is a major cause of nosocomial infection.
What are two high-risk groups for P. aeruginosa infection?
Cystic fibrosis patients
Burn patients
Why are patients with cystic fibrosis at increased risk for infection?
The cilia of patients with cystic fibrosis are unable to effectively clear the organism from the respiratory tract.
What are four virulence factors of P. aeruginosa?
Pili (type 4)
Glycocalyx
Toxin
Extracellular products
How do Pili (type 4)
Glycocalyx
Toxin
Extracellular products contributed to pathogenesis?
Pili mediate attachment to the host's cells; the capsule is antiphagocytic.
What toxins and extracellular products are produced by P. aeruginosa?
Extracellular pigments
Endotoxin
Exotoxins A and S
Extracellular protease (elastase and alkaline protease)
Cytotoxin
Hemolysins
What pigments does P. aeruginosa produce?
Usually green (pyoverdin) and blue (pyocyanin) pigments, but may also produce red and black pigments.
What part of the endotoxin contributes to pathogenesis?
Lipid A moiety.
What is the action of exotoxin A?
Adenosine diphosphate (ADP) ribosylates and inactivates elongation factor (EF-2), thereby inhibiting mammalian protein synthesis.
Diphtheria toxin produced by Corynebacterium diphtheriae acts by this mechanism.
What is the action of exotoxin S?
ADP ribosylates specific guanosine triphosphate (GTP)-binding proteins.
What are four common infections caused by P. aeruginosa?
1) Urinary tract infections
2) Wound infections
3) Pneumonia
4) Sepsis
What is the mortality rate for P. aeruginosa sepsis?
50%
What are three less-common infections caused by P. aeruginosa?
1) Malignant otitis externa
2) Folliculitis
3) Corneal infections
How is P. aeruginosa infection diagnosed?
Growth on blood or MacConkey agar and biochemical tests.
What is noticeable about P. aeruginosa growth on culture?
Fruity-aroma
How is P. aeruginosa treated?
Two bactericidal antibiotics are given simultaneously to prevent resistance.
What classes of antibiotics can be used for treatment?
Aminoglycosides, antipseudomonal Beta-lactams, and quinolones.
What other species of Pseudomonas cause human infection?
1) Burkholderia mallei
2) Burkholderia cepacia
3) P. pseudomallei
How does B. mallei differ from other species of Pseudomonas?
It is nonmotile
What infection does B. mallei cause?
Glanders
Which is more common in horse, donkeys, and mules
What are the clinical manifestations of B. mallei?
Depending on the route of infection, it can cause:
1) Acute, localized suppurative infection of the eye, nose or lips
2) Acute pulmonary infection
3) Acute septicemic infection that is usually fatal.
4) Chronic suppurative infection with multiple subcutaneous or intramuscular abscesses.
What disease does P. pseudomallei cause?
Melioidosis
What are the clinical manifestations of P. pseudomallei?
Symptoms are similar to B. mallei infection.