EXPERIMENTAL FOREIGN-BODY ASSOCIATED INFE CTIONS

The problem of implant-associated infection has been an increasing con cern since foreign materials were used in surgery. Several animal mode ls have been developed to study different aspects of such infections. The tissue-cage model is especially suitable to analyse the role of an timicrobial agents in device-related infections. This model perfectly simulates the human situation in the sense that no spontaneous healing occurs, and short-term therapy with most antibiotics does not result in the complete elimination of the implant-associated bacteria. Quinol ones have been increasingly used in the treatment of device-related bo ne and joint infections. We therefore studied the role of quinolones a gainst Staphylococcus aureus infection in the foreign-body model. In a dditions, we analysed the effect of rifampin-quinolone combinations. C iprofloxacin and fleroxacin completely failed to eradicate infections with six clinical isolates of S. aureus. In contrast, rifampin alone o r in combination was highly efficacious in eliminating tissue-cage ass ociated S. aureus infections. The most important difference between th ese two types of antibiotics was the complete inability of quinolones to kill stationary-phase staphylococci, whereas rifampin had a good ba ctericidal activity not only against growing, but also against station ary-phase S, aureus. In conclusion, the experimental data favour the u se of rifampin-quinolone combinations in the treatment of implant-asso ciated infections due to S. aureus.