IN VITRO ACTIVITY OF LINEZOLID AGAINST CLINICAL ISOLATES OF METHICILLIN RESISTANT STAPHYLOCOCCUS
AbstractBackground: Staphylococcus is responsible for a variety of medical problems, including skin and softtissue infections (SSTIs), surgical site infections (SSIs), endocarditis and hospital acquired bacteraemia.Methicillin resistance in staphylococcus has become a global problem limiting the treatment modalitiesto a large extent. Methods: The aim of this study was to evaluate the in vitro activity of linezolid andother antibiotics against clinical isolates of methicillin resistant staphylococcus (n=163); including 105methicillin resistant Staphylococcus aureus and 58 methicillin resistant coagulase negativestaphylococci. Antibiogram of these isolates was determined by the Kirby-Bauer disc diffusion methodand minimum inhibitory concentration of linezolid was determined by standard agar dilution method.Results: Overall methicillin resistant S. aureus showed high multi-drug resistance. ATCC 25923Staphylococcus aureus and ATCC 29213 Staphylococcus aureus were used as the standard controlstrains. MIC90 of linezolid was comparable for methicillin resistant coagulase negative staphylococciand methicillin resistant S. Aureus (4.0 mg/L); however at MIC50 linezolid was two fold more activeagainst methicillin resistant coagulase negative staphylococci (1mg/L) than methicillin resistant S.aureus (2mg/L). Conclusion: It is concluded that linezolid has excellent activity against methicillinresistant staphylococci including multidrug resistant strains.Keywords: Linezolid, MIC, MRSA, MRCoNS
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