The microbiological efficacy of the combination of fosfomycin and vancomycin against clinically relevant staphylococci.

Infections with multiresistant strains of Staphylococcus aureus and Staphylococcus epidermidis pose severe clinical problems. The drug of choice in such cases, vancomycin, is potentially ototoxic and nephrotoxic and this may give rise to additional problems in the patient. Fosfomycin has been shown to be nephroprotective when given with vancomycin and with other nephrotoxic drugs. We report the inhibitory and bactericidal activity of fosfomycin and vancomycin alone and in combination against 26 clinically relevant strains of S. aureus and 48 strains of S. epidermidis. In most instances these two drugs showed indifferent or additive effects, synergism or antagonism was only rarely observed. Assessment of the bactericidal action of the combination revealed similar effects. The combination of fosfomycin and vancomycin may, therefore, be beneficial in clinical situations where the nephrotoxic effect of vancomycin cannot be tolerated.