Comparison of methicillin, nafcillin, and oxacillin in therapy of Staphylococcus aureus endocarditis in rabbits

J Lab Clin Med. 1977 Jun;89(6):1262-8.

Abstract

Methicillin (M), nafcillin (N), and oxacillin (OX) (400 mg administered intramuscularly every 8 hours) were compared in the therapy of left-sided endocarditis in rabbits infected with two different strains of Staphylococcus aureus. The three antibiotics were equally effective in eliminating staphylococci from cardiac vegetations. N and OX were four to eight times as active against the staphylococci as M in broth but had equivalent activity in serum. The peak M and OX levels in serum were at least twice the peak N level, but the half-life of N in the serum (2.1 hours) was about three times that of M (0.6 hours) and twice that of OX (1.1 hours). Serum bactericidal activity tests demonstrated essentially equal activity with the three antibiotics 1 and 2 hours after injection; however, at 4 and 6 hours N had an advantage over M and OX. Therefore, despite clear differences in vitro activity, protein binding, and pharmacodynamics, M, N, and OX were equally effective in therapy of staphylcoccal endocarditis in rabbits.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Endocarditis, Bacterial / drug therapy*
  • Endocarditis, Bacterial / microbiology
  • Endocardium / microbiology
  • Female
  • Methicillin / administration & dosage
  • Methicillin / blood
  • Methicillin / therapeutic use*
  • Microbial Sensitivity Tests
  • Nafcillin / administration & dosage
  • Nafcillin / blood
  • Nafcillin / therapeutic use*
  • Oxacillin / administration & dosage
  • Oxacillin / blood
  • Oxacillin / therapeutic use*
  • Rabbits
  • Sepsis / drug therapy
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / drug effects

Substances

  • Nafcillin
  • Methicillin
  • Oxacillin