In vitro activity of cefmenoxime, cefotaxime, latamoxef, cefazolin, nafcillin and vancomycin against 53 endocarditis and bacteremic strains of Staphylococcus aureus.

Antistaphylococcal activity of newer beta-lactam antibiotics, cefmenoxime, cefotaxime and latamoxef was compared with that of the more conventional antistaphylococcal agents, nafcillin, cefazolin and vancomycin. 53 strains of Staphylococcus aureus, 40 from patients with endocarditis and 13 from patients with bacteremia from other causes were tested in vitro against each antibiotic using agar dilution methods. Minimal concentration of antibiotic to inhibit 90% of strains tested was 2 micrograms/ml for cefmenoxime and cefotaxime, 8 micrograms/ml for latamoxef and only 0.5 microgram/ml for nafcillin, cefazolin and vancomycin. The newer beta-lactam antibiotics may not be preferred to nafcillin, cefazolin or vancomycin in the treatment of serious staphylococcal infections.