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;
36 Cards in this Set
- Front
- Back
|
What does S. aureus look like?
|
Spherical and grape like
|
|
|
S. aureus contains what biochemical fxns? (2)
|
catalase
coagulase |
|
|
Is S. aureus gram neg or pos?
|
Pos
|
|
|
Is S. aureus aerobic, anaerobic, or facultaive?
|
Facultative anaerobe
|
|
|
What are the 4 structural component (virulence factors)?
|
capsule
peptidoglycan teichoic acid protein A |
|
|
what are the 4 toxins (virulence factors)?
|
cytotoxin (alpha, beta, delta)
exfoliative toxins enterotoxins TSS toxin |
|
|
what is the biological effect of the capsule?
|
inhibits phagocytosis
|
|
|
What is the Biological effect of peptidoglycan? (2)
|
fever
abcess |
|
|
What is the biological effects of teichoic acid?
|
disrupts cell membrane potential
|
|
|
what is the biological effects of Protein A?
|
binds Fc portion of IgG and prevents Ab-mediated clearance of Ag
|
|
|
What is the biological effect of cytotoxin (alpha, beta and delta)?
|
Lyses cells
|
|
|
What is the biological effects of the exfoliative toxin?
|
seperates dermis and epidermis
|
|
|
What is the biological effect of the enterotoxin?
|
superantigen, and causes GI problems
|
|
|
What is the biological effect of the TSS toxin?
|
superantigen, and lysis of endothelial cells causing leakage.
|
|
|
Superantigen
|
crosslinks TCR and MHC II and sends fake signals to release cytokines (IL-1 and TNF alpha). It overreacts the immune system and can cause TSS
|
|
|
What is the 2 S. Aureus diseases(2)
|
1) localized pyogenic infection
2 Disseminated toxic mediated infection |
|
|
Localized pyogenic infections (9)
|
Impetigo
folliculitis furuncles carbuncles wound inf endocarditis pneumonia osteomyletis Septic arthritis |
|
|
Disseminated toxic mediated infections (3)
|
TSS
SSSS (staphylococcal scalded skin syndrome) food poisoning |
|
|
S. aureus is the number one cause of what poisoning?
|
food poisoning
|
|
|
Where is S. aureus (normal flora) found on our bodies?
|
skin. Breaking of skin can lead to disease.
|
|
|
What are the 4 S. aureus cutaneous infections?
|
Impetigo
Furuncles (boils) carbuncles SSSS |
|
|
Impetigo
|
superficial pus filled vesicle
|
|
|
Furuncles (boils)
|
nodules containing necrotic tissue and pus
|
|
|
Carbuncles
|
deeper tissue furuncles
|
|
|
SSSS (3)
|
1) usually occurs in infants
2) results from exfoliative toxin 3) TOXIN MEDIATED |
|
|
What are the 4 non-cutaneous infections?
|
bacteremia
endocarditis osteomyelitis pneumonia |
|
|
Bacteremia
|
bac in blood stream.
|
|
|
Osteomyelitis
|
Infection of bone. painful, high fever and prululent discharge at site
|
|
|
Food poisoning (causes)
|
TOXIN MEDIATED
ham, pork, potato salad, ice cream. Contamination occurs when someone handles these products with a skin infection or inf of nasopharyngeal fluid |
|
|
TSS (3)
|
TOXIN MEDIATED
1) menstrating women 2) hyperabsorbant tampons 3) fever, HTN, rash |
|
|
S. aureus is has shown resistance against which antibiotics? (3)
|
PCN
methicillin Vancomycin |
|
|
Diagnosis of S. aureus (7)
|
1) Gram stain
2) Catalase 3) Coagulase 4) Hemolysin 5) Blood Agar (sheep blood) 6) Agar (7.5% NaCl, Mannitol) 7) blood cultures |
|
|
How is food poisoning diagnosed?
|
clinical history
|
|
|
Why would you use 7.5% NaCl and mannitol in a Agar plate when you are trying to grow S. aureus?
|
NaCl inhibits growth of most organisms and mannitol is fermented mainly by staph, not other organisms
|
|
|
What 3 conditions are toxin mediated?
|
SSSS
TSS Food poisoning |
|
|
What is pyogenic?
|
bac that causes pus or abcesses
|
