Exam 2: Staphylococcus

Question 1

What tests can be used to identify staphylococcus?

Answer 1

Coagulase test

Catalase positive

Question 2

Describe coagulase test

Answer 2

React with prothrombin in the serum in the presence of coagulase reacting factor, forming staphylothrombin
Staphylothrombin convert fibrinogen to fibrin

Question 3

What is commonly used in the coagulase test?

Answer 3

Rabbit serum

Question 4

What is the catalase positive test?

Answer 4

Biochemical test differentiates from streptococcus

Question 5

What are the 5 species that are coagulase tube test positive?

Answer 5

S. aureus
S. intermedius
S. pseudointermedius
S. delphini
S. schleiferi subspecies coagulans

Question 6

What are the natural hosts of S. aureus?

Answer 6

Humans (nasal carriers) and primates, but phenotypes have adapted to other animals, especially in cattle

Question 7

What is S. pseudointermedius the most common resident of?

Answer 7

Skin and hair coat of dogs

Question 8

What is S. delphini the resident of?

Answer 8

Dolphins

Question 9

What tests can differentiate S. aureus?

Answer 9

Slide coagulase or MSA fermentation

Question 10

What is complete hemolysis caused by?

Answer 10

α, δ, and γ hemolysin

Question 11

What is incomplete hemplysis caused by?

Answer 11

β-hemolysin

Question 12

What cell wall antigens are considered to be virulence factors for staphylococcus?

Answer 12

Peptidoglycan
Teichoic acid
Capsular polysaccharide

Question 13

What is teichoic acid?

Answer 13

A polymer of glycerol phosphate

Question 14

What membrane proteins are considered to be virulence factors for staph?

Answer 14

Protein A
Clumping factor A and B
Staphylokinase
MSCRAMMs (microbial surface components recognizing matrix molecules)

Question 15

What does protein A react with?

Answer 15

Fc of IgG

Question 16

Is protein A phagocytic or antiphagocytic? What does this mean?

Answer 16

Antiphagocytic

Promotes evasion of or interference with host immune system

Question 17

What does clumping factor A and B dp?

Answer 17

Binds to fibrinogen

Induces adherence to host epithelial cells

Question 18

What does staphylokinase do?

Answer 18

Activates plasminogen to plasmin, which digests fibrin clot

Serine protease activity: degrade C3b and IgG

Question 19

What do MSCRAMMs do?

Answer 19

Induce adherence and invasion to host epithelial cell

Question 20

What are the different causes of clear or complete hemolysis?

Answer 20

Alpha hemolysin
Delta hemolysin
Gamma or Epsilon hemolysin

Question 21

What does alpha hemolysin cause?

Answer 21

Leukocidal
Cytocidal
Vasoconstriction
Necrosis (skin and udder)

Question 22

What does delta hemolysin cause?

Answer 22

Leukocidal

Necrosis

Question 23

What does gamma or epsilon hemolysin cause?

Answer 23

Weak hemolysis

Question 24

What causes incomplete hemolysis?

Answer 24

Beta hemolysin

Question 25

What secretory toxins and enzymes are considered to be virulence factors for staph?

Answer 25

Leukocidins

Exofoliative toxins

Question 26

What do exofoliative toxins cause?

Answer 26

Blistering skin disease: scalded skin syndrome (occurs in pigs)

Question 27

All staphylococcal enterotoxins are superantigen. What does this mean?

Answer 27

Directly binds to T cell receptor and MHC II

Massive T cell activation

Question 28

What can some staphylococcal enterotoxins cause?

Answer 28

Food poisoning

Question 29

What can urease and phosphatase cause as a virulence factor?

Answer 29

Calculi formation

Question 30

What is quorum sensing?

Answer 30

Regulating virulence factors by signaling molecules, autoinducing peptide

Question 31

Does staphylococcus cause any unique diseases or conditions?

Answer 31

No, but there are a few exceptions

Question 32

What is the most common host response to staphylococcus?

Answer 32

Pyogenic

Question 33

What is one of the diseases that is caused by S. hyicus?

Answer 33

Exudative seborrheic dermatitis/greasy pig disease