Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
70 Cards in this Set
- Front
- Back
|
What is the gram stain of Legionella?
|
Gram neg rods
|
|
|
What type of flagellum does legionella have? What do they use it for?
|
Unipolar, one; used for propelling it around in water.
|
|
|
What are the growth requirements of Legionella?
|
-Fastidious
-Obligate aerobes -L-cysteine / ferric iron |
|
|
What is the main energy source for Legionella species?
|
Amino acids
|
|
|
What does gram staining of legionella show?
|
That it stains weakly
|
|
|
What are the 2 infections caused by Legionella?
|
-Legionaire's disease
-Pontiac fever |
|
|
How are ~1/4 of Legionella infections transmitted?
|
Nosocomially
|
|
|
What type of pathogen is Legionella in terms of how it is in cells?
|
Facultative intracellular
|
|
|
How does Legionella survive within phagocytes?
|
By altering their endocytic trafficking systems.
|
|
|
How does Legionella alter the endocytic trafficking system?
|
By shoving virulence effectors right into the macrophage cytosol
|
|
|
How does Legionella get its virulence effectors into macrophage cytosols?
|
By a type IV secretion system.
|
|
|
What other bug uses a type IV secretion system?
|
Helicobacter (CagA)
|
|
|
What are the 3 bugs that survive intracellularly by altering endocytic trafficking?
|
-Legionella
-Brucella -Chlamydia |
|
|
What is the host reservoir of Legionella in the environment?
|
Amoebae
|
|
|
What are the virulence factors produced by Legionella?
|
cytotoxins
hemolysins endotoxins lipases proteases |
|
|
And how do these virulence factors get into the macrophage?
|
By the type IV secretion system
|
|
|
How does Legionella resist being killed by ROI's while it's in the macrophage cytosol?
|
By preventing phagolysosomal fusion
|
|
|
Where does L. pneumophilia live?
|
In natural and manmade water sources and in wet soil.
|
|
|
Why does Legionella pneumophilia live in amoeba?
|
Because they're very similar to alveolar macophages.
|
|
|
How do humans acquire legionella infections?
|
By droplet transmission
|
|
|
What type of infection does Legionella cause?
|
Opportunistic
|
|
|
Is Legionella normal flora?
|
No; it's always a pathogen
|
|
|
In general what type of diseases are caused by Legionella?
|
Lung infections that result in respiratory distress.
|
|
|
What symptoms are seen in Legionaire's disease?
|
Acute pneumonia symptoms
|
|
|
What symptoms are seen in Pontiac fever?
|
Acute Influenza-like symptoms
|
|
|
What species causes Legionaire's disease and Pontiac fever?
|
L. pneumophilia
|
|
|
What determines which disease will develop?
|
It's not known
|
|
|
Which disease has a faster onset?
|
Pontiac fever - 12 hours
Legionaire's takes 2-10 days |
|
|
Which disease has a more severe progression?
|
Legionaire's is worse
|
|
|
Which one can cause death?
|
Legionaire's if untreated.
|
|
|
How is Pontiac fever treated?
|
It is usually self-limiting.
|
|
|
What cells respond to a Legionella infection?
|
-Peripheral blood monocytes
-PMNs |
|
|
What do the monocytes do?
|
Transform into tissue macrophages
|
|
|
What is needed in order to prevent bacterial multiplication of the legionella bugs?
|
Activated Macrophages
|
|
|
What happens if macrophages aren't activated?
|
Legionella can prevent phagolysosomal fusion, persist and proliferate.
|
|
|
What 2 cytokines are responsible for the fever and associated systemic symptoms?
|
-IL1
-TNFalpha |
|
|
What happens if Legionaire's disease is left untreated?
|
The bugs cause lysis of lots of host phagocytes, releasing enzymes from those and them selves too
|
|
|
What does all the enzyme release from phagocytes and legionella bugs do?
|
Destroys the lung tissue
|
|
|
What are 4 ways to identify Legionella? Which is best?
|
-DFA (best)
-Culture (fastidious) -ELISA (not all serotypes) -Serology (may take 3 weeks) |
|
|
What is the recommended treatment for Legionaire's disease that is community acquired?
|
Erythromicin or Rifampin
|
|
|
What is the recommended treatment for Legionaire's disease that is nosocomially acquired?
|
Azithromycin or Levofloxacin
|
|
|
What is the treatment for Pontiac fever?
|
Nothing it's self limiting
|
|
|
What is the gram stain of Pseudomonas aeruginosa?
|
Gram neg bacillus
|
|
|
Is it motile?
|
yes
|
|
|
What are Pseudomonads often seen doing?
|
Forming biofilms and microcolonies on inanimate plastic objects like catheters
|
|
|
What is the distinct way we can tell Pseudomonas apart from enterics?
|
Oxidase positive
|
|
|
What is the energy source for Pseudomonas?
|
Carbs
|
|
|
What does Pseudomonas do on enteric media?
|
Nothing it doesn't ferment
|
|
|
What does Pseudomonas do in CTA tubes?
|
Oxidizes glucose, xylose, fructose, and galactose.
|
|
|
What does P. aeruginosa do on BA?
|
Strongly hemolytic
|
|
|
What 2 pigments are virulence factors of P. aeruginosa?
|
-Pyoverdin
-Pyocyanin |
|
|
What type of infection does P. aeruginosa often cause?
|
Nosocomial
|
|
|
What patients are susceptible to P. aeruginosa infections?
|
-Cystic fibrosis
-Severe burn patients -Deep puncture wound patients |
|
|
Why does P. aeruginosa commonly cause death in CF patients?
|
Because it converts from a nonmucoid to a mucoid phenotype
|
|
|
What are 6 virulence factors produced by P. aeruginosa?
|
ACEPEP
|
|
|
What does ACEPEP stand for?
|
-Adhesins
-Capsule (polysaccharide) -Endotoxin -Pigments -Exotoxins -Proteases |
|
|
What do the Adhesins do?
|
Promote adherence to the host
|
|
|
What does Alginate mean?
|
That the polysaccharide capsule is drippy on agar
|
|
|
How are the pigments Pyocyanin and Pyochelin toxic?
|
The cause release of oxygen radicals from host cells.
|
|
|
What do the exotoxins of P. aeruginosa do?
|
cause extensive tissue damage
|
|
|
What is the main effect of the polysaccharide capsule of P. aeruginosa?
|
Formation of biofilms and microcolonies
|
|
|
What type of infection does P. aeruginosa normally cause in
-CF patients -Burn patients -Catheterized patients |
CF = lung/pulmonary
Burn = skin Catheter = UTI |
|
|
What are 3 nonhospital infections P. aeruginosa can cause?
|
-Otitis media from swimming pools
-Eye infections from extended wear contact lenses -Bacteremia/endocarditis |
|
|
What is the most effective way to ID Pseudomonas aeruginosa?
|
Culture
|
|
|
What are 2 other Pseudomonads that cause infections in humans?
|
-Burkholderia cepacia
-Burkholderia pseudomallei |
|
|
What are the top 3 anatomical sites for acquiring nosocomial infections?
|
1. Urinary tract
2. Surgical wound 3. Respiratory tract |
|
|
What organism is the predominant cause of nosocomial UTI?
|
E. coli
|
|
|
What 3 organisms are the predominant causes of nosocomial surgical wound infections?
|
-S. aureus
-E. coli -Bacteroides |
|
|
What 3 organisms are the predominant causes of nosocomial respiratory infections?
|
-Klebsiella pneumo
-Pseudomonas aeruginosa -Staph aureus |
|
|
What type of nosocomial infection has the highest fatality rate? What bugs usually cause it?
|
Bacteremia - due to GNB
|
