Surveillance for the variance of the MICs to vancomycin,teicoplanin and linezolid of methicillin-resistant Staphylococcus aureus in five years

Objective To review and analyze the evolution of the MICs of vancomycin,teicoplanin and linezolid in methicillin-resistant Staphylococcus aureus(MRSA) strains isolated in our hospital from 2003 to 2007.Methods The MICs of vancomycin,teicoplanin and linezolid were tested by E-test method on a sample of randomly selected MRSA strains.Results The incidences of MRSA increased from 52.2% in 2003 to 74.5% in 2007,vancomycin MIC geometric mean increased from 1.85 μg/ml in 2003 to 2.15 μg/ml in 2007,and teicoplanin MIC geometric mean increased even markedly more from 1.28 μg/ml in 2003 to 2.07 μg/ml in 2007.The linezolid MIC remained almost unchanged.Conclusion The incidences of MRSA increased from 2003 to 2007,there was a upward trend in glycopeptide MIC geometric means over the years,and this increase was higher for teicoplanin than for vancomycin.