Staphylococci Flashcards Preview

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Flashcards in Staphylococci Deck (17):
0

What does S.aureus have to surround its huge peptidoglycan layer?

A microcapsule.

1

What proteins that disable our immune system does S.aureus have?

1. Protein A
2. Coagulase
3. Hemolysins
4. Leukocidins
5. Penicillinase
6. Novel penicillin binding protein

2

What is the role of protein A?

Sites that bind the Fc portion of IgG. This may protect the organism from opsonization and phagocytosis.

3

What is the role of coagulase?

Fibrin formation around the bacteria, protecting it from phagocytosis.

4

What is the role of hemolysins?

4 types: alpha, beta, gamma, delta.
Destroy RBCs, neutrophils, macrophages, platelets.

5

What is the role of leukocidins?

Destroy leukocytes.

6

What leukocidin does CA-MRSA produce?

Panton-Valentine leukocidin (PVL), which is associated with a propensity to form abscesses.

7

What is the role of novel penicillin binding protein?

Also called transpeptidase - is necessary for cell wall peptidoglycan formation and is inhibited by penicillin.

8

What protein does S.aureus have to tunnel through tissue?

1. Hyaluronidase
2. Staphylokinase
3. Lipase
4. Protease

9

What is the role of staphylokinase?

It lyses formed fibrin clots (like streptokinase).

10

What is the exotoxin weaponry of S.aureus?

1. Exfoliatin - scalded skin syndrome.
2. Enterotoxins - heat stable.
3. Toxic shock syndrome toxin (TSST-1).

11

What percentage of S.aureus have TSST-1?

20%.

12

What exotoxin-mediated diseases can S.aureus produce?

1. Gastroenteritis (food poisoning)
2. Toxic shock syndrome
3. Scalded skin syndrome

13

What diseases resulting from direct organ invasion can S.aureus produce?

1. Pneumonia
2. Meningitis
3. Osteomyelitis
4. Acute bacterial endocarditis
5. Septic arthritis
6. Skin infections
7. Bacteremia/sepsis
8. UTI

14

What skin infections can staphylococci cause?

1. Impetigo
2. Cellulitis
3. Local abscesses, furuncles, and Carbuncles
4. Wound infections

15

How can an infection with S.epidermidis occur?

Compromised patients with Foley catheters or IV lines can become infected when this organism migrates from the skin along the tubing.

16

What does S.epidermidis cause?

Nosocomial infections:
1. Prosthetic joints
2. Prosthetic heart valves
3. Sepsis from IV lines
4. UTI