Antimicrobial Therapy 2

Question 1

What is the MOA for Beta-lactam antibiotics?

Answer 1

Blocks the transpeptidation of PG; Targets PBP on inner surface of cell wall; Osmotic fragility and cell lysis

Question 2

What are the classes of Beta-lactams?

Answer 2

1. Penicillins
2. Cephalosporins
3. Carbapenems
4. Monobactams

Question 3

What are the Pharmacokinetics of Beta-lactams?

Answer 3

Bactericidal, Time dependent killing

Question 4

What are the side effects of Beta-lactams?

Answer 4

Rash, diarrhea, vaginitis

Question 5

Describe Beta-lactam resistance

Answer 5

1. Beta lactamase
2. ESBLs
3. Mutations to binding site on PBPs(MRSA)
4. Impaired penetration and Efflux pumps

Question 6

How do we overcome Beta-lactamases?

Answer 6

Clavulanic acid

Question 7

What are the pharmacokinetics of Penicillin?

Answer 7

Widely distrubuted in most tissues except the prostate; Renally cleared

Question 8

Specific side effects of Penicillins?

Answer 8

1. Sodium or Potassium overload with IV
2. Beta-lactamase inhibitors increase diarrhea
3. Ampicillin/Amoxicillin increase risk of rash if concurrent viral infection

Question 9

What are the allergies associated with Penicillins?

Answer 9

1. Hypersensitivity reaction
2. Serum sicknes
3. Seizures in patients with renal failure.
4. Cross reactivity to all penicillins and beta-lactams except Monobactam and aztreonam.

Question 10

What is the MOA of cephalosporins?

Answer 10

In addition to its Beta-lactam MOA, it also INCOPORATES itself into the cell wall once bound to PBP.

Question 11

What side effects are specific to cephalosporins?

Answer 11

1. Enterocolitis
2. Cefotetan Can block alcohol metabolism by inhibiting aldehyde dehydrogenase
3. Ceftriaxone causes biliary sludging (Bilirubin)

Question 12

Are cephalosporins vulnerable to beta-lactamases?

Answer 12

NO; Their structure prevents beta-lactamase enzymatic destruction. Extended spectrum antibiotic

Question 13

Discuss resistance to cephalosporins?

Answer 13

1. ESBLs; ESBLs do NOT affect cefotetan or Carbapenems.

Question 14

Describe First generation of cephalosporins

Answer 14

First generation cephalosporins cant penetrate the CNS good penetration into urine.

Question 15

Describe Second generation cephalosporins

Answer 15

Poor CNS penetration, Cefotetan maintains activity against ESBL-producing organisms; No PSA activity.

Question 16

Describe Third Generation cephalosporins

Answer 16

Used to treat meningitis; Penetrates CNS well

1. Low MW
2. Non-ionized at physiological pH
3. Highly lipid soluble

Question 17

When do you NOT use a third generation cephalosporin?

Answer 17

1. Neonates with hyperbilirubenemia

2. Not renally cleared; secreted into bile and excreted in feces.

Question 18

Discuss Fourth Generation Cephalosporins

Answer 18

1. Good CNS penetration.

2. Good activity in PSA

Question 19

What are the pharmacokinetics specific to Carbapenems?

Answer 19

1. Broadest spectrum of activity
2. Resistance can develop when treating PSA
3. Renally cleared

Question 20

What are the side effects of Carbapenems?

Answer 20

1. Leukopenia, Neutropenia, and thrombocytopenia

2. Imipenem decreases seizure threshold

Question 21

Describe resistance to Carbapenems?

Answer 21

Mutation resulting in abscence of OM porin in gram -

Question 22

Explain administration of Imipenem

Answer 22

1. Hydrolyzed by dehydropeptidase

2. Must be given with cilastatin

Question 23

What is the side effect of Monobactams?

Answer 23

Increase in liver function test and transient eosinophilia.

Question 24

What are the 5 inhibitors of cell wall synthesis?

Answer 24

Inhibit formation of PG

1. Vancomycin
2. Telavancin
3. Dalbavancin
4. Oritavancin
5. Bacitracin

Question 25

What are the pharmacokinetics of Vancomycin?

Answer 25

1. Bactericidal 2. Concentration-dependent killing 3. Widely distributed 4. Cant cross BBB

Question 26

What are the side effects of Vancomycin?

Answer 26

1. Nephrotoxicity 2. Chills 3. Fever 4. Rash 5. Red neck syndrome

Question 27

Discuss the resistance to Vancomycin.

Answer 27

1. Prolonged use | 2. Modification to binding site.

Question 28

Discuss Telavancin side effects

Answer 28

1. Taste disturbances 2. Vomiting 3. Insomnia 4. Foamy urine 5. Prolonged QT-interval

Question 29

What are the pharmacokinetics of Bacitracin?

Answer 29

1. Gram + only | 2. Topical application

Question 30

Side effects of Bacitracin?

Answer 30

Nephrotoxicity

Question 31

What is the MOA of Daptomycin?

Answer 31

Binds to CM via calcium dependent insertion of its lipid tail; Disrupts ionic gradient.

Question 32

What are the pharmacokinetics of Daptomycin?

Answer 32

1. Minimum CNS penetration 2. Gram + only 3. Bacteriocidal

Question 33

Side effects of Daptomycin?

Answer 33

1. Constipation 2. Myopathy 3. Headache