Antibiotics

Question 1

Mode of action of β-lactam anx

Answer 1

inhibit bacterial cell wall synthesis by targeting the activity of bacterial
transpeptidases known as penicillin-binding proteins
(PBPs).

Question 2

How did Staph MR arise?

Answer 2

due to mutations in
the mecA and mecC genes, which encode for the PBP2a
enzyme that has a low affinity for β-lactam antimicrobials.
Therefore, PBP2a continues to build bacterial cell
walls even in the presence of β lactam drugs, which
leads to the resistant phenotype.

Question 3

mecC VS mecA

Answer 3

For mecA encoded
oxacillin resistance the activity of PBP2a is dependent
on the presence of a functional native PBP2 to provide
the transglycosylation activity in addition to its own
transpeptidase activity. The PBP2a produced by the
mecC gene appears to be unique from that produced
by the mecA gene because it does not require a functional
native PBP2 to produce high-level oxacillin resistance.
4

Question 4

What are the strains of MRSA that caused the majority of canine and feline MRSA in North AM?

Answer 4

The health care associated ones such us MRSA America 100

Question 5

MRSAstrain USA 500?

Answer 5

Horses and human CA MRSA

Question 6

LA -MRSA (Large animal)

Answer 6

ST398

Question 7

To which abx can P. aeruginosa e intrinsically resistan?

Answer 7

aminopenicillins, most
cephalosporins (except ceftazidime), chloramphenicol,
TMS, and tetracyclines. Acquired

Question 8

Acquired resistance Pseudomonas

Answer 8

Aminoglycosides, carbapenems, fluoroquinolones