High-level resistance to aminoglycosides in enterococci; incidence and alternative active antibiotic combinations in vitro.

Enterococci with high-level resistance to aminoglycosides have been frequently isolated from clinical specimens in the last few years. It is well known that this resistance is linked to a lack of synergism of the beta-lactam/aminoglycoside combination used in the treatment of severe infections. Many authors have reported an increasing incidence of isolation of enterococci highly resistant to gentamicin. In order to overcome the failure of the currently used antimicrobial combinations, in this work the degree of activity of ciprofloxacin plus, respectively, the glycopeptides vancomycin and teicoplanin, and also the combination teicoplanin/netilmicin, was evaluated. The results obtained with ciprofloxacin/teicoplanin and teicoplanin/netilmicin combinations show a good percentage of synergy (about 70-80%) with respect to the combination of ciprofloxacin plus vancomycin. The results are encouraging also in the highly resistant strains.