Post-antibiotic effect of linezolid and vancomycin against methicillin-resistant Staphyloccus aureus

Objective To investigate the post-antibiotic effect(PAE) of linezolid and vancomycin against methicillin-resistant Staphyloccus aureus(MRSA).Methods PAE of linezolid and vancomycin against MRSA was determined by plate colony counting at different concentrations(1×MIC,2×MIC,4×MIC,8×MIC) and different time points(1,2,3 h).The morphological changes of MRSA during the PAE period were observed by scanning electron microscopy.Results All strains were susceptible to linezolid and vancomycin.The PAE was greater at higher concentration and longer exposure time.There was no morphological change of MRSA during the PAE.Conclusion It was demonstrated that linezolid and vacomycin had a moderate in vitro PAE against MRSA.There was no morphological change of MRSA during the PAE.