Ch 3. Clinical Bacteriology- Gram + saph. cocci

Question 1

name 3 main features of gram + cocci

Answer 1

spherical
non-sporing
non motile

Question 2

_____ is the virulence factor in the cell wall of staph

fxn:

Answer 2

Protein A

fxn: binds to Fc frag of IgG at complement site = no activation of the complement (cant neutralize)

Question 3

5 toxins of staph:

1. leukocidins:_
2. hemolysin: ___
3. enterotoxins: ___
4. exfoliation: ___
5. TSS: ___

Answer 3

1. leukocidins: damage WBC
2. hemolysin: hemolysin of RBC
3. enterotoxins: food poisoning
4. exfoliation: scalded skin sx
5. TSS: stim large amt of IL-1* , IL-2, TNF

Question 4

2 enzymes that staph produces

Answer 4

Coagulase : clotting
• converts fribrogen → fibrin (virulence factor)

Hyaluronidase: hyaluronic acid → break down CT & WBC

Question 5

what are the 3 strands of staph?

Answer 5

staph aureus
stap epidermidis
staph saprophytics

Question 6

pyogenic infection caused by s. aureus

Answer 6

osteomyelitis

Question 7

shape of staph

Answer 7

grape like clusters

Question 8

describe the blood agar of:

1. aureus
2. epidermidis
3. saprophytics

Answer 8

1. aureus: yellow colony- clear zone of hemolysis
2. epidermidis: white
3. saprophytics: white

Question 9

What are the 2 main differences btw aureas vs epidermidis & saprophytics

Answer 9

aureas is :

Hemolysin +ve (clear zone on bl agar)
Coagulase +ve

Question 10

staph is ___ +ve: degrades H2O2 into water and O2

Answer 10

catalase