Staphylococcus

Question 1

Appearance of staph on slides?

Answer 1

clusters of grapes!

Question 2

Are staphylococcus commensals?

Answer 2

yes, they’re found normally in the skin and mucous membranes

Question 3

coagulase

Answer 3

walls of necrotic areas to form abscesses

Question 4

Protein A and fibronection

Answer 4

extracellular proteins that help staph adhere to host cells

Question 5

4 Stages of Abscess Formation

Answer 5

1. Release of bacterial products and host-derived complements
2. Infiltration by neutrophils (inflammation)
3. Neutrophil lysis by leukocidin
4. Coagulase to wall off and form abscess

Question 6

Staphylococcus aureus

Answer 6

principal pathogenic staph specials, makes yellow/gold colonies (aureus = gold) due to staphyloxanthin pigment

Question 7

Staphylococcus pseudointermedius

Answer 7

Major cause of UTIs (and matrix for uroliths) and pyoderma

Question 8

Is canine pyoderma caused by one or multiple species?

Answer 8

mixed infections!

Question 9

exfoliative toxin (chymotrypsin serine protease)

Answer 9

produced by staph and splits the stratum granulosum

Question 10

Staphylococcus chromosome cassettes

Answer 10

carry methicillin resistant genes

Question 11

Should you treat pyoderma empirically?

Answer 11

no, it’s rarely an emergency, get the susceptibility test

Question 12

Greasy Pig Disease pathogen and mechanism?

Answer 12

Staph. hyicus, secretes exfoliating toxin and degrades desmoglein 1 (just like dogs)

Question 13

Most severe mastitis pathogen in bovine, ovine, caprine?

Answer 13

Staphylococcus aureus –> gangrene and anscesses
(tx only effective in 50% of cases, so cull or blind the quarter)