[Synergy between tobramycin and netilmicin on three strains of methicillin and gentamicin resistant staphylococci (S. epidermidis, S. aureus)].

The antibacterial effect of tobramycin-netilmicin combination on multiresistant strains of staphylococcus was performed to determine the signification of synergy images on diffusion plates. Meticillin and gentamicin resistant strains of S. epidermidis (2 strains) and S. aureus (1 strain) were examined and showed an index of combined effect < 0.05 demonstrating synergy. These values were obtained with aminoglycoside concentrations < or = 4 mg/l, levels which can be considered as pharmacologically acceptable. This synergic action can be explained by specific inhibition of the resistance enzyme in the strains, possibly in combination with a cooperative effect on the classical targets of aminoglycosides. This type of combination using tobramycin and netilmicin could define a new use of aminoglycosides based on the conception of combining antibiotic enzyme inhibition.