Anti-microbial (cell wall)

Question 1

Clinical use

Mostly used for G+ organisms (S. pneumoniae, S. pyogenes, Actinomyces). Also used for N. meningitidis & T. pallidum.

considered bacterialcidial for G+ cocci, G+ rods, G- cocci and spirochetes. Penicillinase sensitive

Drug, MOA, Toxicity, Resistance

Answer 1

• Drug: Penicillin G, V
  
  • Penicillin G (IV & IM form), Penicillin V (oral)
  • Protype Beta-lactam antibiotics
• MOA:
  
  • Bind penicillin-binding proteins (transpeptidase),
  • blocks transpeptidase cross linking of peptidoglycan
  • activate autolytic enzymes
• Toxicity: Hypersensitivie rx, hemolytic anemia
• Resistance: Penicllianse in bacteria (a type of Beta-lactamase) cleaves Beta-lactam ring

Question 2

Clinical use

Extended spectrum penicillin: Haemophilus influenzae, E. coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, Shigella, enterococci

Drug, MOA, toxicity, resistance

Answer 2

• penicillinase-sensitive penicillins
  
  • Ampicillin, amoxicillin, aminopenicillins
• MOA:
  
  • wider spectrum than penicillinase sensitive,
  • also combine with clavulanic acid to protect against Beta-lactamase
• Tox: Hypersenistiive rxn, rash, pseudomembranous colitis
• Resistance: penicillinase in bacteria (B-lactamase) cleaves B-lactam ring.

Question 3

Clinical use

S. aureus (except MRSA; resistant bc of altered penicillin-binding protein target site)

Drug, MOA, toxicity, resistance

Answer 3

• Penicillinase-resistant penicillins
  
  • Dicloxacillin,Oxacillin, nafcillin
• Same as penicillin, narrow spectrum
  
  • penicillinase resistant b/c of bulky R group blocks access of B-lactamase to beta-lactam ring
• _​_Tox: hypersistivity rxn, interstitial nephritis

Question 4

Clinical use

Pseudomonase spp. and G- rods, susceptible to penicillinase; use w/Beta-lactamase inhibitors.

Drug, MOA, toxicity, resistance

Answer 4

• Antipseudomonals
  
  • Ticarcillin, piperacillin
• MOA: same as penicillin, extended specturm
• Toxicity: Hypersensitivity rxn

Question 5

What is often added to peniciilin antibiotics to protect the antibiotic from destruction by B-lactamase (penicillinase)?

What makes up the compound?

Answer 5

• Beta-lactamasae inhibitors
• CAST
  
  • Clavulanic Acid
  • Sulbactam
  • Tazobactam

Question 6

Cephalosporins

(I-V)

• MOA
• Toxicity

Answer 6

• MOA
  
  • B-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinase.
  • Bactericidal
• Toxicity
  
  • Hypersensitivity rxn, Vit. K def
  • Low cross-reactivity with penicillins
  • Inc nephrotoxicity of aminoglycosides

Question 7

What drugs are used to treat

G+ cocci, Proteus mirabilis, E. coli, Klebsiella pneumoniae.

PECK

• _ _ used prior to surgery to prevent _ _ wound infection.

Answer 7

• 1st generatino
  
  • cefazolin, cephalexin
• Cefazolin used prior to surgery to prevent S. auerus wound infection

Question 8

What drugs are used to treat

G+ cocci, H. influenzae, Enterobacter aerogenes, N. spp, Proteus mirabilis, E. coli, Klebsiella pneumoniae, Serratia marcescens

HEN PEcKS

Answer 8

Cefoxitin, cefaclor, cefuroxime

Question 9

What drugs are sued to treate serious gram - infections resistant to other B-lactams

• meningitis and gonorrhea
• pseudomonas

Answer 9

• Ceftriaxone: Meningitis & Gonorrhea
• Ceftazidime: Pseudomonas

Question 10

What drugs are used to

• inc activity against pseudomonas and G+ organisms
• Broad G+ and G- organism coverage inclduing MRSA, does not cover pseudomonas.

Answer 10

• Cefepime (4th gen)
• Ceftaroline (5th gen)

Question 11

Clinical use

G- rods only,

no activity against G+ or anaerobes. For peniclin allergic pt and those with renal insufficiency who cannot tolerate aminoglycosides

Drug, MOA, toxicity, resistance

Answer 11

• Aztreonam (monbactam)
• MOA:
  
  • a monobactam, resistant to B-lactamase.
  • Prevent peptidoglycan cross linking by binding to penicillin-binding protein 3
  • synergistic w/aminoglycosides, no cross-allergenicity w/penicillins.
• Toxicity: Usually nontoxic, occasional GI upset

Question 12

Clinical use

G+ cocci, G- rods, and anaerobes. Wide spectrum, but significant side effects limit use to life-threatening infections or after other drugs have failed.

• _ _ has a dec risk of seizures and is stable to dehydropeptidase I.
• _ _ ( a moa) is added to dec inactivation of drug in renal tubules

Drug, MOA, toxicity, resistance

Answer 12

• Meropenem, Ertapenem, doripenem, imipenem
• MOA: imipenem is a broad spectrum, B-lactamase, resistant carbapenem.
  
  • Always admi w/ cilastatin (inhibitor of renal dehydropeptidase I) to dec inactivation of drug in renal tubules
• toxicity: GI distress, skin rash, and CNS toxicity (seizures) at high plasma levels

Question 13

Clinical use

G+ only- serious multidrug resistant organisms, include MRSA, enterococci and C. difficile (oral dose for pseudomembranous colitis).

Drug, MOA, toxicity (Well tolerated but NOT trouble free) , resistance

Answer 13

• Vancomycin
• MOA: inhibits cell wall peptidoglycan formation by binding D-ala-D-ala portion of cell wall precursors. Bactericidal.
• Toxicity:
  
  • Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing
  • red man syndrome: can largely prevent by pretreatment w/antihistamines and slow infusion rate
• Resistance: occurs in bacteria via aa modification
  
  • D-ala D-ala to D-ala D-lac
  • Pay back 2 D-alas (dollars) for vandalizing (vancomycin)