Cell Wall Active Agents

Question 1

Fosfomycin

1) Mechanism of Action
2) Use
3) Spectrum

Answer 1

1) Non-Beta-Lactam Drug-inhibits synthesis of PeptiDoGlycan (PDG) building block
2) SINGLE DOSE for uncomplicated UTIs
* Multiple doses leads to resistance*
3) Broad Spectrum

Question 2

Bacitracin

1) Mechanism of Action
2) Use
3) Spectrum

Answer 2

1) Non-Beta-Lactam Drug-depletes lipid carrier (bactoprenol) for PDG synthesis
2) Skin & Ophthalmic infections
* Topical Application ONLY d/t SEVERE nephrotoxicity*
3) Narrow Spectrum-Gram+

Question 3

Vancomycin

1) Mechanism of Action
2) Use
3) Spectrum

Answer 3

1) Non-Beta-Lactam Drug-binds D-Ala-D-Ala teminus of pentapeptide blocking the 2 steps of PeptiDoGlycan (PDG) synthesis–>transglycosylation and transpeptidation
2) SERIOUS Gram+ infections resistant to other drugs
3) Narrow Spectrum-Gram+, MRSA
* *Red Man Syndrome Toxicity**

Question 4

Penicillin G/Penicillin V

1) Mechanism of Action
2) Use

Answer 4

1) Beta-Lactam Drug-inhibit transpeptidases (aka Penicillin Binding Proteins-PBPs) blocking PeptiDoGlycan (PDG) strand cross-linking
2) Non-Beta-Lactamase-producing microbes, Gram+ and Gram- cocci
* Main adverse effect=allergy*
* *Stevens-Johnson Syndrome Toxicity-rare**

Question 5

Describe the differences of Penicillin G vs. Penicillin V

Answer 5

Penicillin G: Parental administration

Penicillin V: Oral administration

Question 6

Dicloxacillin/Nafcillin

1)Mechanism of Action

Answer 6

1) Beta-Lactamase-resistant penicillin-inhibit transpeptidases (aka Penicillin Binding Proteins-PBPs) blocking PeptiDoGlycan (PDG) strand cross-linking
2) Penicillinase-producing Streptococci and Staphylococci

Question 7

Amoxicillin

1) Mechanism of Action
2) Use

Answer 7

1) Extended Spectrum Penicillin-inhibit transpeptidases (aka Penicillin Binding Proteins-PBPs) blocking PeptiDoGlycan (PDG) strand cross-linking
2) Gram+ and some non-lactamase producing Gram- bacilli
* Generally combined w/Beta-Lactamase inhibitors like Clavulanic Acid b/c they are NOT Beta-Lactamase resistant*

Question 8

Ticarcillin

1) Mechanism of Action
2) Use

Answer 8

1) Extended Spectrum Penicillin-inhibit transpeptidases (aka Penicillin Binding Proteins-PBPs) blocking PeptiDoGlycan (PDG) strand cross-linking
2) Anti-pseudomonal
* Generally combined w/Beta-Lactamase inhibitors like Clavulanic Acid b/c they are NOT Beta-Lactamase resistant*

Question 9

Piperacillin

1) Mechanism of Action
2) Use

Answer 9

1) Extended Spectrum Penicillin-inhibit transpeptidases (aka Penicillin Binding Proteins-PBPs) blocking PeptiDoGlycan (PDG) strand cross-linking
2) Anti-pseudomonal, Klebsiella
* Generally combined w/aminoglycoside like gentamycin/streptomycin*

Question 10

Clavulanic Acid

1)Use

Answer 10

1)Used in fixed ratios w/extended spectrum penicillins

Question 11

Cefazolin

1) Mechanism of Action
2) Generation
3) Use

Answer 11

1) Similar to PCNs-inhibits cell wall synthesis
2) 1st Generation
3) Broadest Spectrum-Gram+ cocci, Gram- bacilli
* Surgical Prophylaxis*

Question 12

Cefoxitin

1) Mechanism of Action
2) Generation
3) Use

Answer 12

1) Similar to PCNs-inhibits cell wall synthesis
2) 2nd Generation
3) Extended Gram- coverage and activity against anaerobes

Question 13

Ceftriaxone

1) Mechanism of Action
2) Generation
3) Use

Answer 13

1) Similar to PCNs-inhibits cell wall synthesis
2) 3rd generation
3) anti-pseudomonal and anti-pneumococcal, Serious Gram- infections like meningitis, pneumonia

Question 14

Cefepime

1) Mechanism of Action
2) Generation
3) Use

Answer 14

1) Similar to PCNs-inhibits cell wall synthesis
2) 4th Generation
3) Anti-pseudomonal, high resistance to Beta-Lactamases

Question 15

Imipenem

1) Mechanism of Action
2) Use
3) Spectrum

Answer 15

1) Beta-Lactam Drug, Similar to PCNs-binds more efficiently to penicillin binding proteins (PBPs)
2) Infections resistant to other agents
* Active against extended spectrum Beta-Lactamase organisms*
3) Broadest activity of ALL Beta-Lactam Drugs
* *Generally combined w/Cilastatin to prevent inactivation of Imipenem**

Question 16

Cilastatin

1) Mechanism of Action
2) Use

Answer 16

1) inhibits dehydropeptidases (which usually degrade imipenem)
2) Combined with Imipenem

Question 17

Aztreonam

1) Mechanism of Action
2) Use
3) Spectrum

Answer 17

1) Binds penicillin binding proteins (PBPs), relatively resistant to Beta-lactamases
2) Gram- UTIs, lower RTIs
3) Narrow Spectrum-limited to Gram - aerobes including Pseudomonas
* Can penetrate inflamed CNS*

Question 18

Daptomycin

1) Mechanism of Action
2) Use

Answer 18

1) Cell membrane agent-Membrane depolarization
2) VRE, MRSA
* Can cause Myopathy*