MOAs

Question 1

Rifamycins (MOA)

Answer 1

Prevents transcription: binds to RNA polymerase and blocks mRNA elongation

Question 2

Aminoglycosides (MOA)

Answer 2

Mismatch of tRNA d/t messing up codon

Binds to 30s on ribosome

Question 3

Macrolides and Ketolides (MOA)

Answer 3

Prevents peptide bonds between AAs by inhibiting peptidyltransferase
Ketolides( two binding sites = tighter binding)
Binds to 50s on ribosome (reversibly)

Question 4

Tetracyclines (MOA)

Answer 4

Prevents tRNA binding, blocking protein synthesis
Glycylcyclines: Prevents recognition by efflux pumps
Binds to 30s on ribosome

Question 5

Chloramphenicol (MOA)

Answer 5

Blocks formation of peptide bonds

Binds to 50s on ribosome

Question 6

Clindamycin (MOA)

Answer 6

Inhibits protein synthesis

Binds to 50s on ribosome

Question 7

Streptogramins (MOA)

Answer 7

Inhibits protein synthesis (Dalfo. helps bind of quinu).

Binds to 50s on ribosome - overlaps with macrolides and clindamycin.

Question 8

Linezolid (MOA)

Answer 8

Prevents association with 30s, resulting in preventing formation of first peptide bond in ribosomes.
Binds to 50s.

Question 9

Nitrofurantoin (MOA)

Answer 9

MOA Unclear, but concentrates in urine.

Question 10

Sulfas (MOA)

Answer 10

Sulfamethoxazole: Mimics PABA and competitively inhibits DHT Synthetase.

Trimethoprim: Inhibits dihydrofolate reductase

Reduces production of folic acid.

Question 11

Quinolones (MOA)

Answer 11

Binds to DNA Gyrase (G-) and Topoisomerase IV (G+) to inhibit DNA gyrase

Cross resistant with carbapenems in pseudomonas

Question 12

Metronidazole (MOA)

Answer 12

Small molecule, passively diffuses into bacteria. Breaks DNA through nitro group, forming free radicals. Anaerobes have electron transport chain that donate electron to nitro group to form super oxide.

Question 13

Carbapenems (MOA)

Answer 13

Cell wall synthesis disruption. Use porins to penetrate G-, resistant to most beta lactamases.

Question 14

Monobactams AKA Aztreonam(MOA)

Answer 14

Binds well to PBPs and resistant to beta lactamases.

Question 15

Glycopeptides (MOA)

Answer 15

Large molecule, can’t pass through porins.

Question 16

Daptomycin (MOA)

Answer 16

Lipid portion inserts into bacterial membrane to form ion conduction channel --> cell death
no PNA (inactivated by surfactant)

Question 17

Colistin (MOA)

Answer 17

Polymyxin. Fatty acid tail inserts into membrane, displacing Ca and Mg, increasing permeability and resulting in cell lysis.