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34 Cards in this Set
- Front
- Back
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What is the gram stain, oxygen requirements, and shape of pseudomonas?
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Gram negative rods, aerobic
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What is the natural environment for pseudomonas bacteria?
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Soil and water
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What are two other pathogens associated with pseudomonas which used to be in the same genus?
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Stenotrophomonas maltophila and burkholderia cepacia
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Patients with what disease are often infected by pseudomonas and related organisms?
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Cystic fibrosis
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What bacteria is a common cause of wound infections contaminated with fresh water?
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Aeromonas hydrophila
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What soil bacteria was seen in soldiers in the Iraq war and is an emerging nosocomial problem?
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Acinetobacter baumannii
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Describe the cultural growth characteristics of pseudomonas
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It is a strict aerobe that can adapt to low nutrient conditions and is resistant to disinfectants and antibiotics; utilizes over 80 compounds for growth (grows on any medium)
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What is the major virulence factor for pseudomonas?
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The capsule
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Describe the capsule of pseudomonas
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It contains a polysaccharide slime layer that is anti-phagocytic and a mucoid capsule (alginate) in cystic fibrosis strains
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What is the effect of exotoxins and enzymes secreted by pseudomonas?
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Tissue damage and inhibition or killing of phagocytes
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What pigment is secreted by pseudomonas?
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pyocyanin, which is toxic for leukocytes
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Where does pseudomonas aeruginosa live?
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In water reservoirs of hospitals and any place that has water
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Describe the transmission of pseudomonas
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It is transmitted by the hands of hospital personnel and direct contact with contaminated equipment
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How is pseudomonas acquired?
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It is usually acquired as a nosocomial illness but can be community acquired
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What are the major clinical manifestations of pseudomonas infection?
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1)nosocomial pneumonia (2) cystic fibrosis pneumonia (3) burn or wound infections (4) UTI infections (5) Dermatitis (6) Corneal infections (7) Endocarditis
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Describe the conditions of nosocomial pseudomonas pneumonia
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It occurs in patients who are immunocompromised with common septicemia and high mortality rate
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Describe the conditions of cystic fibrosis pseudomonas pneumonia
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It is a chronic progressive lung destruction with a change to the mucoid capsule; no bloodstream invasion
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What is a common finding in burn or wound infections with pseudomonas aeruginosa?
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Green pus and septicemia
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What is the most likely cause of a pseudomonas UTI?
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Urinary catheter
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What is the pathogenesis of a pseudomonas dermatits?
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Moist skin from extended exposure to contaminated water; more severe in diabetics and immunocompromised
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Explain the pathogenesis of a pseudomonas endocarditis
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It generally occurs with IV drug abuse; injection of bacteria directly into the blood
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Describe the treatment of pseudomonas
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It is resistant to many antibiotics and 2 drug therapy is often required
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What is legionnaires disease?
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Acute pneumonia caused by legionella pneumophila
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What is the natural habitat for legionella?
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Fresh water aquatic habitats and inside intracellular parasites (protozoa)
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Describe the gram stain, oxygen requirements, catalase and oxidase status of legionella
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It is gram negative but stains poorly with the gram stain, strict aerobe, catalase and oxidase positive
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Where does legionella grow in humans?
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inside macrophages
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Where is legionella commonly found in the hospital ?
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In the buildings water system
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Describe the transmission of legionella
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It is inhaled from aerosols from contaminated building water sources; does NOT have human to human transmission
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What are the major clinical presentations of legionella infections?
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Legionnaires disease and Pontiac fever
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Describe the pathogenesis of legionnaires disease
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Legionnaires disease is an acute pneumonia associated with intracellular multiplication in alveolar macrophages
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What is Pontiac fever?
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A mild, self-limiting respiratory disease with no pneumoina
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What is the most common diagnostic tool used for diagnosis of legionella?
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Urine antigen test (high specificity and sensitivity)
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How is legionella and pseudomonas infection prevented?
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Monitoring and disinfection of water reservoirs
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What is the most common type of legionella?
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legionella pneumophila serotype 1
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