ABx B

  1. Mechanisms of ABx Resistance
    • ● Enzymatic destruction of drug (β-lactamases)
    • ● Impaired penetration of antibiotic to target PBPs (transpeptidase)
    • ● Modification of target PBPs (binding site)
    • ● Rapid ejection of the drug (efflux)
  2. PCN + B-lactamase Inhibitor
    No antibacterial activity by themselves because they only have half of the beta-lactam part, used in combination to act as a decoy and consume the penicillinase/beta-lactamase and keep the antibiotic or penicillin protected
  3. Carbapenems BS Activity
    • ● Advantages at three different sites allows broader spectrum and increased efficacy
    • → Improved penetration of porins
    • → Enhanced binding to PBP (transpeptidase)
    • → Increased resistance to b-lactamases
  4. Imipenem (Carbapenem) with Cilastatin (Primaxin)
    • ● Inhibit renal dehydropeptidase
    • ● Imipenem is inactivated by dehydropeptidase in renal tubules
  5. Bacitracin Advantage
    No cross resistance between Bacitracin and other antimicrobial agents
  6. Sulfonamide / Trimethoprim Combination
    • ● Combination is bactericidal
    • ● Trimethoprim + sulfamethoxazole
    • ● Sulfadiazine + pyrimethamine 
    • ● Sulfadoxine + Pyrimethamine (Fansidar)
  7. Sulfonamides Ineffective Against
    • ● Rickettsiae
    • ● Anaerobes
    • ● Pseudomonas
  8. Aminoglycosides + B-lactam
    • ● Extend coverage to gram+ pathogens
    • ● Take advantage of the synergism between these two classes of drugs
    • ● Enterococcal endocarditis
    • ● Shorten duration of therapy for
    • → Viridans streptococcal infections
    • → Staphylococcal endocarditis
  9. Tetracycline Absorption
    • ● Food (except doxycycline and minocycline)
    • ● Divalent cations (Ca2+, Mg2+, Fe2+) or Al3+
    • ● Dairy products and antacids, which contain multivalent cations
    • ● Alkaline pH
  10. Methenamine CI w/Sulfonamides
    Sulfonamides should not be given at the same time because they may form an insoluble compound with the formaldehyde released by methenamine (exacerbate crystalluria)
Author
ebmalonzo
ID
316186
Card Set
ABx B
Description
ID 1 (Final): ABx (B)
Updated