Antimicrobial Therapy 3

Question 1

Which antibiotics act on 30S Ribosomal Subunit?

Answer 1

1. Tetracyclines

2. Aminoglycosides

Question 2

What is the MOA for Tetracyclines?

Answer 2

Inhibit bacterial protein synthesis by binding to 30S ribosome; Causes misreading of genetic code

Question 3

What are the Pharmacokinetics of Tetracyclines?

Answer 3

1. Bacteriostatic
2. Broad Spectrum
3. Requires Active and passive transport to cross cell wall

Question 4

When do you not use Tetracyclines?

Answer 4

Don’t use in pregnancy and when breastfeeding; Chelates with calcium inhibits bone and teeth formation in fetus. Avoid until eruption of permanent teeth

Question 5

What are the mechanisms of resistance for Tetracyclines?

Answer 5

1. Enzymatic inactivation
2. Impaired influx by protein pump
3. Proteins protecting binding site Tet(M) mutation

Question 6

What are the side effects of Tetracycline?

Answer 6

1. NVD
2. Photosensitivity
3. Teeth discoloration
4. Bone deformities
5. Liver toxicity

Question 7

Discuss Tigecycline

Answer 7

Withstands resistance that affects other tetracyclines.

1. Broad spectrum
2. Great tissue penetration

Question 8

What is the MOA for Aminoglycosides?

Answer 8

Used for Aerobic Gram-

1. Inteferes with initiations complex
2. Induces misreading of mRNA
3. Breaks up polymers into nonfunctional monomers

Question 9

What are the pharmacokinetics of Aminoglycosides?

Answer 9

1. Bactericidal
2. Concentration depedent killing
3. Small Volume of distribution; cant cross BBB
4. Post antibiotic effect

Question 10

What are the mechanisms of resistance for Aminoglycosides?

Answer 10

1. Enzymatic inactivation
2. Impaired entry into cell
3. Ribosome mutation

Question 11

How do aminoglycosides get into bacterial cell?

Answer 11

1. Passive diffusion across Gram- OM

2. Active transport across CM via oxygen dependent process

Question 12

What are the side effects of Aminoglycosides?

Answer 12

1. Neuromuscular blockade
2. Ototoxicity
3. Nephrotoxicity

Question 13

Which drugs act on the 50s Ribosomal subunit?

Answer 13

1. Macrolides
2. Clindamycin
3. Streptogramins
4. Oxazolidinones

Question 14

What is the MOA of Macrolides?

Answer 14

Binds to 50S ribosome by blocking transpeptidation and translocation reaction.

Question 15

What are the pharmacokinetics of Macrolides?

Answer 15

1. Bacteriostatic

2. Good distribution

Question 16

What is the resistance of Macrolides?

Answer 16

1. Reduced permeability
2. Esterases hydrolyze macrolides
3. Production of methylase that modifies ribosome.

Question 17

What are the side effects of Macrolides?

Answer 17

1. Abdominal pain
2. Cholestatic hepatitis
3. Prolonged Qtc interval
4. Skin rash

Question 18

Discuss Fidaxomicin

Answer 18

1. Used for C. difficile diarrhea
2. Bacteriocidal
3. Large MW

Question 19

What is the MOA of Clindamycin?

Answer 19

Inhibits translocation reactions on 50s ribosomes

Question 20

What are the pharmacokinetics of Clindamycin?

Answer 20

1. Bacteriostatic
2. Good distribution
3. Treats abscesses

Question 21

What are the side effects of Clindamycin?

Answer 21

1. Skin rash
2. Nausea
3. Diarrhea

Question 22

What is the MOA for Streptogramins?

Answer 22

Dalfopristin- Causes conformational change in ribosome preventing peptide chain formation.
Quinupristin: Blocks elongation of peptide; Binds 50s

Question 23

What are the pharmacokinetics of Streptogramins?

Answer 23

1. Bactericidal
2. Inhibits Cyp450
3. Synergistic combination

Question 24

What are the side effects of Streptogramins?

Answer 24

1. Thrombocytopenia
2. Hyperbilirubinemia
3. Arthralgia-Myalgia Syndrome

Question 25

What is the MOA for Oxazolidinones?

Answer 25

Linezolid: Binds 23s ribosome subunit preventing formation of ribosome complex Tedizolid: Binds P site of 50s subunit of bacterial ribosome; Prevents protein synthesis

Question 26

Are Oxazolidinones Bacteriostatic?

Answer 26

YES

Question 27

What are the side effects of Oxazolidinones?

Answer 27

1. Thrombocytopenia 2. Neutropenia 3. Serotonin Syndrome

Question 28

What is the MOA of Fluroquinolones?

Answer 28

Inhibit bacterial topoisomerases

Question 29

What are the pharamcokinetics of Fluroquinolones?

Answer 29

1. Bactericidal 2. Time and concentration dependent killing 3. Renally cleared except Moxifloxacin

Question 30

Which drugs inhibit DNA replication?

Answer 30

Fluoroquinolones, Metronidazole, and Rifampin

Question 31

What are the mechanisms of resistance of Fluoroquinolones?

Answer 31

1. Altered target sites 2. Altered Cell wall permeability 3. Active efflux pump

Question 32

What are the side effects of Fluoroquinolones?

Answer 32

1. Photosensitivity 2. QT prolongation 3. May damage cartilage; Avoid in pregnancy

Question 33

What is the MOA for Metronidazole?

Answer 33

Disrupts DNA and inhibits nucleic acid synthesis in anaerobic bacteria

Question 34

What are the pharmacokinetics of Metronidazole?

Answer 34

1. Bactericidal | 2. Good for anaerobic infections

Question 35

What are the side effects of Metronidazole?

Answer 35

1. Dry mouth 2. Pancreatitis 3. Nausea

Question 36

What is the MOA of Rifampin?

Answer 36

Binds beta-subunit of DNA-dependent RNA polymerase; Inhibits RNA synthesis (No effect on elongation)

Question 37

What are the pharmacokinetics of Rifampin?

Answer 37

1. Bactericidal 2. Good bioavailibility 3. CYP450 inducer

Question 38

What is the resistance to Rifampin?

Answer 38

Point mutation to beta subunit of RNA polymerase

Question 39

What are the side effects of Rifampin?

Answer 39

1. Orange body fluid 2. Rash 3. Thrombocytopenia 4. Cholestatic jaundice

Question 40

What is the MOA of Nitrofurantoin?

Answer 40

Interferes with metabolism, protein and cell wall synthesis

Question 41

What are the side effects of Nitrofurantoin?

Answer 41

1. Nausea 2. Vomiting 3. Neuropathies and hemolytic anemia in G6PD deficiency.