L5 - Gram Postivie Cocci (1/20)

Question 1

The most common canine Staphylococcus isolate is;

A. Staphylococcus aures
B. Staphylococcus pseudintermedius
C. Staphylococcus hyicus
D. Staphylococcus epidermidis

Answer 1

B. Staphylococcus pseudintermedius

Note: 
Staphylococcus aures (More common in humans);
Staphylococcus hyicus (pigs); 
Staphylococcus epidermidis (a coagulase - stap; can cause opportunistic pathogens in humans and animals)

Question 2

Blackie, a 5yro female dog was presented to the vet clinic with unresolving skin lesions. Purulent and bloody exudate was oozing out of some of the lesions. Which of the following Staphylococcus species is most commonly involved in this type of cases in dogs?

A. Staphylococcus aures
B. Staphylococcus pseudintermedius
C. Staphylococcus hyicus
D. Staphylococcus epidermidis

Answer 2

B. Staphylococcus pseudintermedius

Note: Bc it is a dog

Question 3

Staphylococcal enterotixin exerts its pathogenic effect by;

A. Binding indiscriminately and nonspecifically to the T cell receptor and Class II MHC molecule
B. Binding to receptor using the B subunit and activation of an enzyme using the A subunit
C. Binding to the CD 14 receptor and activating macrophages to release TNF alpha

Answer 3

A. Binding indiscriminately and nonspecifically to the T cell receptor and Class II MHC molecule

Note: Staphylococcal enterotixin = A Superantigen, binds to more number of cells (non-specific binding)

Question 4

Which of the following antimicrobial does not belong to B-lactam group?

A. Ampicillin
B. Imipenem
C. Cephalosporins
D. Enrofloxacin

Answer 4

D. Enrofloxacin

Note: Impienem (A beta-lactam; always given IV);

Question 5

Mechanism of action of B-Lactam group is by:

A. Inhibiting protein synthesis
B. Inhibiting cell wall synthesis
C. Inhibiting nucleic acid synthesis
D. Inhibiting efflux pumps

Answer 5

B. Inhibiting cell wall synthesis

Note: check if this is correct answer

Question 6

One of the adverse effects of using beta-lactam such as penicillin in certain individuals is;

A. Development of methicillin resistance
B. Development of clindamycin resistance
C. Type IV hypersensitivity
D. Type I hypersensitivity

Answer 6

D. Type I hypersensitivity

Question 7

Tetracyclines

Answer 7

• A broad spectrum antibiotic (active against Gram +, Gram -, Mycoplasma, Chlamydia, Ehrlichia, Rickettsia, Anaplasma, Mycobacterium and protozoan parasites)
• Widely used in ruminants and swine
• Inhibit protein synthesis (bind to 30s ribosome)
• Bacteriostatic
• Time dependant antimicrobials
• Members: Oxytetracycline, Chlortetracycline, Doxycycline, Minocycline