Bacteria

Question 1

What is the gram stain result of staphylococcus?

Answer 1

Gram + cocci in clusters

Question 2

What are the structural features of staphylococcus?

Answer 2

Capsule, slime layer, teichoic acid

Question 3

What is the result catalase test for staphylococcus?

Answer 3

Catalase positive

Question 4

What species of staphylococcus is/are coagulase positive?

Answer 4

S. aureus

Question 5

What species of staphylococcus is/are coagulase negivative?

Answer 5

S. epidermidis and S. saprophyticus

Question 6

What are the virulence factors of S. aureus?

Answer 6

Protein A, teichoic acid, polysaccharide capsule

Question 7

What is the function of protein A

Answer 7

Binds Fc region of IgG inhibiting complement activation and phagocytosis

Question 8

What exotoxins does S. aureus produce?

Answer 8

Enterotoxin, TSST, exfoliative toxins, alpha, beta, delta, gamma toxins, Panton-Valentine leukocidin

Question 9

What exotoxin is associated with food poisoning?

Answer 9

Enterotoxin

Question 10

What is the function of teichoic acid?

Answer 10

Attachment

Question 11

What exotoxin causes scalded skin syndrome?

Answer 11

Exfoliative toxin (ETA and ETB)

Question 12

What is the mechanism of exfoliative toxin

Answer 12

Serine proteases that cleave a cell adhesion molecule in desmosomes resulting in separation of the epidermis

Question 13

What is the mechanism of alpha, beta, delta, and gamma toxins?

Answer 13

Damage cell membrane and cause cell lysis in RBCs and neutrophils

Question 14

What virulence factor enzymes are produced by S. aureus?

Answer 14

Coagulase and fibrinolysin, hyaluroidase, proteases, nucleases, lipases