[Evaluation of the use of rifampin combinations in severe staphylococcal infections. Apropos of the selection of 7 resistant mutants].

Selection of rifampicin-resistant Staphylococcus aureus has been described in vitro and in vivo when this compound is given as monotherapy or orally. That this occurrence may be prevented by combination antibiotic therapy is generally accepted. We report 25 cases of severe staphylococcal infection treated by a synergistic association of rifampicin with an aminoglycoside, vancomycin, or a macrolide. Therapy failed as a result of selection of the same rifampicin-resistant Staphylococcus aureus (serotype and lysotype) in seven cases. This finding may be explained by insufficient diffusion or inactivation of the other antibiotic in the infection site.