Changes in resistance of Staphylococcus aureus to vancomycin and linezolid in Sichuan Province in 2011-2015

Abstract:

ObjectiveTo investigate the resistance of Staphylococcus aureus (S. aureus) to vancomycin and linezolid in Sichuan Province, and provide reference for clinical antiinfection treatment. MethodsS. aureus and methicillinresistant S. aureus(MRSA) from 71 hospitals in Sichuan Province in 2011-2015 were collected, minimum inhibitory concentration（MIC） values of vancomycin and linezolid against S. aureus and MRSA in each year were calculated. ResultsA total of 51 976 strains of S. aureus were collected in 5 years, 14 361 of which were MRSA, isolation rate of MRSA decreased from 36.02% in 2011 to 25.56% in 2015, which showed a downward trend (χ2=160.72，P＜0.05）. From 2011 to 2015, MIC50 of vancomycin against S. aureus were 1, 0.5, 0.5, 1, and 1μg/mL respectively，MIC90 increased from 1μg/mL to 2μg/mL；the mean MIC50 of linezolid was 2μg/mL，MIC90 increased from 2μg/mL to 4μg/mL. Change in MIC50 and MIC90 of vancomycin against MRSA in 2011-2015 were obvious, which increased from 0.5, 1μg/mL to 2μg/mL respectively；the mean MIC50 of linezolid was 2μg/mL，MIC90 increased from 2μg/mL to 4μg/mL. ConclusionThe isolates rate of MRSA had a decreasing trend，but there is a upward trend of MIC50 and MIC90 of vancomycin and linezolid against MRSA, bacterial resistance surveillance needs to be strengthened to provide evidence for rational clinical antimicrobial therapy.