Objective        To assess whether there is vancomycin minimum inhibitory concentration (MIC) creep in methicillin-resistant Staphylococcus aureus (MRSA) from 6 large-scale hospitals in China by analyzing the MIC of the bacterium to vancomycin

teicoplanin and linezolid over a 5-year period.       Methods       MRSA isolates were collected from 6 hospitals in China during the period from 2007

to 2011. Their MIC to vancomycin

teicoplanin and linezolid was determined by broth microdilution according to the procedure by the National Committee for Clinical Laboratory Standards. MIC

50

MIC

90

and geometric-mean-MIC were calculated for all isolates in each year.       Results       A total of 1 219 clinical isolates of MRSA were determined in this study

All the isolates were susceptible to vancomycin

linezolid and teicoplanin. Overall

the vancomycin geometric-mean-MIC was 0.952

0.956

0.947

1.013 and 1.040 μg/mL respectively in the 5 consecutive years

with a significantly increased trend over years (

P

0.05). The percentages of MRSA isolates with a vancomycin MIC above 1 μg/mL (MIC1 μg/mL) were 23.5%

21.6%

27.8%

30.6% and 42.8% annually

and increased with time（

P

0.05）. The teicoplanin geometric-mean-MIC was 0.739

0.749

0.743

0.768 and 0.973 μg/mL

and also in an increased trend over years（

P

0.05）. The linezolid geometric-mean-MIC was 1.414

1.422

1.386

1.410 and 1.221 μg/mL

and MIC trend was not found （

P

0.05）.       Conclusion       Vancomycin MIC creep in MRSA has emerged in China in this study.