Comparative in vitro activity of teicoplanin and vancomycin against United States teicoplanin clinical trial isolates of gram-positive cocci.

In this study, the in vitro activity of teicoplanin and vancomycin was directly compared against 503 Gram-positive cocci isolated during the U.S. teicoplanin clinical trials. Both antibiotics were equally active against oxacillin-sensitive Staphylococcus aureus, oxacillin-sensitive and oxacillin-resistant Staphylococcus epidermidis, and other coagulase-negative staphylococci, except Staphylococcus haemolyticus. Teicoplanin was fourfold more active than vancomycin against oxacillin-resistant S. aureus (MIC90, 0.5 vs. 2.0 micrograms/ml), whereas vancomycin was more active than teicoplanin (MIC90, 2.0 vs. 8.0 micrograms/ml) against oxacillin-resistant S. haemolyticus. Teicoplanin was two- to eightfold more active than vancomycin against the streptococci and enterococci tested.