Ch 2

Question 1

Staphylococcus coccus in brief

Answer 1

catalase positive, coagulase positive, facultative anaerobe, non-motile, non-sporing and occasionally capsulated.

Question 2

Agar nature

Answer 2

golden yellow pigmentation on nutrient agar and β-hemolytic colonies on blood agar

Question 3

Virulence factors

Answer 3

1.Cell wall associated factors
Peptidoglycan
Teichoic acid
Cell surface adhesins, e.g. clumping factor
Protein A
2. Toxins
Membrane active toxins • Hemolysins—α, β, γ, δ • Leukocidin (or panton valentine toxin)
Epidermolytic toxin (exfoliative toxin)
Enterotoxins
Toxic shock syndrome toxin
4.Extracellular enzymes
Coagulase
Heat stable thermonuclease
Deoxyribonuclease
Staphylokinase (fibrinolysin)
Others—hyaluronidase, lipase, and protease

Question 4

Teichoic acid

Answer 4

made up of ribitol phosphate polymers, helps in adhesion of cocci to mucosal surfaces and inhibits opsonization

Question 5

Cell surface adhesins

Answer 5

Clumping factor/bound coagulase—it is a fibrinogen binding adhesin; responsible for slide coagulase reaction Fibronectin binding adhesin
Collagen-binding adhesin.

Question 6

Protein SpA

Answer 6

Meditaes coagulation reaction
Fc portion of IgG