Efficacy of penicillin G, flucloxacillin, cefazolin, fusidic acid, vancomycin, rifampicin and fosfomycin in muscular infections in mice due to Staphylococcus aureus.

Two strains each of sensitive, penicillinase-producing, methicillin-resistant and "tolerant" Staphylococcus aureus were used to infect mice intramuscularly. The mice were then treated with three doses each of fosfomycin, vancomycin, rifampicin, fusidic acid, penicillin G, flucloxacillin or cefazolin intravenously. Infections due to sensitive strains were effectively treated with all antibiotics investigated except fusidic acid. Fosfomycin, vancomycin, rifampicin and flucloxacillin showed the best activity against penicillinase-producing strains. Fosfomycin and vancomycin were equally effective against infections due to methicillin-resistant S. aureus. Infections caused by "tolerant" strains again responded best to fosfomycin, vancomycin and rifampicin.