Lecture 5

Question 1

What are the mechanisms of action of a/bs? (3)

Answer 1

Cell wall - beta-lactams & glycopeptides

PRO syn - tetracyclines, macrolides, aminoglycosides & more

DNA metabolism - Fluoroquinolones, metronidazole, folate syn inhibitors

Question 2

Min inhibitory [ ] (MIC)

Answer 2

Min [ ] of an a/b that will inhibit the growth of an organism

Question 3

Min bactericidal [ ] (MBC)

Answer 3

Min [ ] of an a/b that will kill an organism

Question 4

Bacteriostatic is MBC ___ 4X MIC

Answer 4

MBC > 4X MIC

Question 5

Bactericidal is MBC ___ 4X MIC

Answer 5

MBC 4X MIC

Question 6

What pharmacodynamic properties of a drug effect your dosing regime?

Answer 6

[ ] & time dependent

Question 7

Why is the [ ] of a drug important when deciding on tx regime?

Answer 7

B/c the activity of the antimicrobial relies on how far you are able to exceed the MIC at the site of the infection

Question 8

Why is the time of a drug important when deciding on tx regime?

Answer 8

Activity of the a/b relies on how long you are able to maintain drug [ ]s above the MIC at the site of infection

Question 9

Describe the mechanism of beta-lactams

Answer 9

Inhibit cell wall syn by binding to penicillin binding PROS (transpeptidases & carboxypeptidases) & prevent the final stage of peptidoglycan syn

Question 10

Are beta-lactams bactericidal or bacteriostatic?

Answer 10

bacteriocidal

Question 11

What a/bs are beta-lactams?

Answer 11

Penicillins
Cephalosporins
Carbapenems
beta-lactamase inhibitors

Question 12

What is the mechanism of action for tetracyclines?

Answer 12

PRO syn inhibitors by binding to the 30S ribosomal subunit

Question 13

Are tetracyclines bactericidal or bacteriostatic?

Answer 13

Bacteriostatic

Question 14

What a/bs are tetracyclines?

Answer 14

Oxytetracycline
Doxycycline
Minocycline

Question 15

What is the mechanism of action for fluoroquinolones?

Answer 15

Inhibit DNA syn by biting to topoisomerase (DNA supercoiling enzyme)

Question 16

Are fluoroquinolones bactericidal or bacteriostatic?

Answer 16

Bactericidal

Question 17

What a/bs are fluoroquinolines?

Answer 17

Naladixic acid - limited spectrum
Ciprofloxacin/enrofloxacin - broad spectrum
Moxifloxacin/levofloxacin - extended spectrum

Question 18

What is the mechanism of action for aminoglycosides?

Answer 18

PRO syn inhibitors

Question 19

Are aminoglycosides bactericidal or bacteriostatic?

Answer 19

bactericidal

Question 20

MLSbK mechanism of action?

Answer 20

PRO syn inhibitors by binding to 50S ribosomal subunit

Question 21

Are MLSbK bactericidal or bacteriostatic?

Answer 21

Bacteriostatic

Question 22

What a/bs are MLSbK? (5)

Answer 22

Macrolides
Lincosamides
Streptogramins
Ketolides
Azalides

Question 23

What is the mechanism of action of Chloramphenicol?

Answer 23

PRO syn inhibitor

Question 24

Are Chloramphenicol a/bs bactericidal or bacteriostatic?

Answer 24

Bacteriostatic

Question 25

What a/bs are banned in food animals?

Answer 25

Chloramphenicol | Metronidazole - carcinogenic

Question 26

What is the mechanism of action of metronidazole?

Answer 26

Damage DNA & interfere with repair mechanisms

Question 27

Is metronidazole bactericidal or bacteriostatic?

Answer 27

Bacteriocidal

Question 28

What type of organisms does metronidazole target?

Answer 28

Anaerobic bacteria Gram positive & negative bacteria

Question 29

What organisms does chloramphenicol target?

Answer 29

broad spectrum gram negatives & positives

Question 30

What organisms do aminoglycosides target?

Answer 30

Staphylococcus

Question 31

What organisms do Tetracyclines target?

Answer 31

Broad spectrum gram positives & negatives

Question 32

What is the mechanism of action for folate syn inhibitors?

Answer 32

Inhibit folic acid syn by competitively binding to the PABA portion of the folate molecule

Question 33

Are folate syn inhibitors bactericidal or bacteriostatic?

Answer 33

Bacteriostatic

Question 34

What organisms do folate syn inhibitors target?

Answer 34

Broad spectrum Gram positives & negatives Protozoans & Toxoplasma

Question 35

When do we use anti-gram positives?

Answer 35

last resort

Question 36

What a/bs are anti-gram positives? (4)

Answer 36

Glycopeptides Lipoglycocpeptides Ozaxolidonones Peptide a/bs