In Vitro Activity and Comparison of Tedizolid with Linezolid and Teicoplanin against Vancomycin-Resistant Staphylococcus aureus Strains

Introduction and Objectives: Staphylococcus aureus is considered as a normal flora by colonization in the nose and skin of humans, yet it is as a major cause of nosocomial infections and a life-threatening pathogen. As the second-generation of Oxazolidones, tedizolid has displayed potent activity against Gram-positive pathogens. The aim of the present study was to determine the frequency and comparison of the minimum inhibitory concentration of tedizolid with linezolid and teicoplanin against the vancomycin-resistant S. aureus isolates .Materials and Methods: This study was done on specimens isolated from hospitalized patients (n = 125) in Golestan province during 2017-2018. After identifying of S. aureus isolates using specific tests, broth microdilution test was used according to CLSI M100-S25(2015) criteria to determine the minimum inhibitory concentration(MIC) of antibiotics.Result: The frequency of vancomycin-resistant S. aureus isolates was 31.4%. Determining MIC of tedizolid showed that all isolates of S.aureus tested were susceptible to tedizolid (MIC, ≤0.5μg/mL), while 95% (MIC, ≤4μg/mL) and 89% (MIC, ≤8μg/mL) of isolates were categorized as susceptible to linezolid and teicoplanin, respectively. The concentration of tedizolid that inhibited 90% of isolates (MIC90) was 0.5μg/mL, 4-fold lower than linezolid(MIC90=2μg/ml) and 16-fold lower than teicoplanin (MIC90= 8μg/mL). There was a significant difference between the frequency of drug- resistance of strains isolated from skin and bone infections, so 94% of teicoplanin- resistant isolates and all strains resistant to linezolid were isolated from patients with bone infections (P<0.05).Conclusion: We conclude that tedizolid has a beneficial effect on clinical isolates of S. aureus, and possesses more potent in vitro activity than the rest agents.

Keywords:

Staphylococcus aureus , Tedizolid , Drug resistance