[Activity of vancomycin and teicoplanin against clinical isolates of Staphylococcus aureus in the period 1994-1999].

Since the emergence of the methicillin-resistant S. aureus (MRSA) in the 1960's, glycopeptides (Vancomycin and Teicoplanin) has been the drugs of choice and commonly the sole antimicrobial agents available for the treatment of serious MRSA and other Gram-positive infections. The emergence of S. aureus with intermediate vancomycin-resistance after 1997 threatens to return us to the era before the development of the antibiotics. Prevention of the further spread of S. aureus strains with intermediate and eventually with full glycopeptide resistance requires enhanced laboratory methods to detect resistance. A total of 361 S. aureus clinical isolates (177 MRSA and 184 MSSA) obtained from 1994 to 1999 in eleven Bulgarian hospitals located in geographically distinct areas of the country were enrolled in the study. Minimal inhibitory concentrations of Vancomycin and Teicoplanin were determined by agar-dilution method according to NCCLS recommendations. MIC50 and MIC90 for Vancomycin were 0.7 and 1 mg/ml, and for Teicoplanin--0.5 and 0.9 microgram/ml. All staphylococcal isolates showed sensitivity to Vancomycin and Teicoplanin. MICs of both glicopeptides against MRSA and MSSA did not differ significantly.