Antibiotics

Question 1

daptomycin resistance

Answer 1

mutation of mprF, addition of L-lysine to phosphatidylglycerol of membrane –> increased positive charge –> repels cationic abx

Question 2

tetracycline resistance

Answer 2

expression of efflux pump; pumps drug out of cell

Question 3

metronidazole resistance

Answer 3

mutation in reducing enzymes (rdxA gene) –> impaired drug activation

Question 4

aminoglycoside resistance

Answer 4

enzyme modification of the abx, altering drug-target binding

Question 5

amoxicillin resistance

Answer 5

beta-lactamase expression!

Question 6

trimethoprim and sulfonamide resistance

Answer 6

drug-insensitive dihydropteroate synthase and DHFR (dihydrofolate reductase) which are the targets of those drugs

sulfonamides to dihydropteroate synthase and trimethoprim and DHFR

Question 7

vancomycin resistance

Answer 7

D-Ala, D-Ala is substituted, so vanco no longer binds to target

Question 8

What is peptidoglycan composed of? What enzymes compose

Answer 8

NAM-NAG-pentapeptide

NAM-NAG created by transglycosylase

transpeptidase crosslinks the pentapeptides

Question 9

What are PBPs?

Answer 9

the transglycosylase, transpeptidase, and carboxypeptidases which attach and cross link peptidoglycan elements

Question 10

Which drugs are beta-lactams?

Answer 10

penicillins, cephalosporins, monobactams, carbapenems

Question 11

Penicillins MOA? Adverse effects?

Answer 11

Bind and inhibit PBPs

Adverse effect is hypersensitivity

Question 12

Narrow spectrum penicillins? Beta-lactamase sensitive?

Answer 12

Penicillin G

Penicillin V

Question 13

Very-narrow spectrum penicillins?

Beta-lactamase sensitive?

Answer 13

Methicillin
Nafcillin
Oxacillin

Beta-lactamase resistant!! good for staph

Question 14

Broad spectrum? Beta-lactamase sensitive?

Answer 14

Ampicillin

Amoxicillin

Question 15

Extended-spectrum? Beta-lactamase sensitive?

Answer 15

Piperacillin
Ticarcillin
Azlocillin

good for gram-negative rods

Question 16

Beta-lactamase inhibitors:

Answer 16

Clavulanic acid

used with amoxicillin!

Question 17

1st generation cephalosporin

• agents?
• activity?

Answer 17

Cefazolin
Cephalexin

gram + cocci

Question 18

2nd generation cephalosporin

• agents?
• activity?

Answer 18

Cefotetan
Cefaclor
Cefuroxime

gram + and some gram -

Question 19

3rd generation cephalosporin

• agents?
• activity?

Answer 19

ceftriaxone
cefotaxime
cefdinir
cefixime

gram + and gram - cocci, many gram - rods; most enter CNS

Question 20

4th generation cephalosporin

• agents?
• activity?

Answer 20

Cefepime

broadest spectrum; enters CNS

Question 21

Cephalosporins MOA? adverse effects?

Answer 21

bind and inhibit PBPs

cause hypersensitivity
disulfiram-effect

Question 22

Monobactams

Answer 22

Aztreonam

bind to PBP, cause hypersensitivity

Question 23

Carbapenems

Agents?
MOA?
Adverse Effects?

Answer 23

Doripenem, imipenem (+ cilastin!!), ertapenem, meropenem

bind to PBPs, cause GI sx