In vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus derived from cystic fibrosis sputum.

We evaluated the in vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) derived from cystic fibrosis (CF) sputum. Teicoplanin had a slightly lower median minimum inhibitory concentration (MIC) for these strains (0.25 micrograms/ml) than did vancomycin (0.5 micrograms/ml). Inoculum size increased the MICs similarly for both drugs, and pH variations did not significantly affect their activity. The presence of serum and sputum in the growth media decreased the activity of both drugs, although this was more pronounced for teicoplanin which is highly protein bound. We conclude that teicoplanin has activity against this pathogen and might be evaluated in clinical protocols designed to address this emerging clinical problem.