MODULE 1: ISOLATION AND IDENTIFICATION OF STAPH SPP.

Question 1

What group of Staph spp. constitute the most pathogenic?

Answer 1

Coagulase-positive

Question 2

Coagulase negative staph. are known to comprise over ____ other species.

Answer 2

30

Question 3

This is the traditional marker for S. aureus but there is no direct evidence that it is a virulence factor.

Answer 3

Coagulase

Question 4

This group of Staph spp. are common commensals of the skins, although some can cause infections.

Answer 4

Coagulase-negative

Question 5

Staph. are gram-____ about ___-___ in diameter.

Answer 5

positive; 0.5-1.0 um

Question 6

Staph. is isolated by streaking it onto solid media such as?

Answer 6

1. Blood Agar
2. Tryptic Soy Agar
3. Heat Infusion agar

Question 7

This agar allows allows halotolerant staphylococci to grow and be isolated from other contaminants.

Answer 7

MSA (contains 7.5% NaCl)

Question 8

_______ of the colony should be performed and tests made for catalase and coagulase production, allowing the coagulase- positive Staphylococcus aureus to be identified quickly.

Answer 8

Gram stain

Question 9

What are the other tests available to confirm the presence of S. aureus?

Answer 9

1. Production of Thermostable Deoxyribonuclease
2. Agglutination w/ latex particles coated with IgG and Fibrinogen