Surveillance of tedizolid activity and resistance: In vitro susceptibility of Gram-positive pathogens collected over 5 years from the United States and Europe

- Gram-positive clinical isolates (n = 11,231) from 2009 to 2013 were studied.
- Tedizolid inhibited 99.7% of all isolates at MIC ≤0.5 mg/L.
- Tedizolid activity was high in S. aureus irrespective of methicillin resistance.
- Tedizolid was equally potent regardless of vancomycin resistance in enterococci.
- Tedizolid was ≥4-fold more potent than linezolid against all groups.

In vitro activity of tedizolid and comparators against 11,231 Gram-positive clinical isolates from the United States (84 centers) and Europe (115 centers) were summarized as part of the Surveillance of Tedizolid Activity and Resistance program between 2009 and 2013. Susceptibility testing was performed according to Clinical Laboratory and Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) interpretations were based on CLSI and European Committee on Antimicrobial Susceptibility Testing criteria. Tedizolid inhibited 99.7% of all isolates at MIC ≤0.5 mg/L; activity was similar regardless of methicillin or vancomycin resistance phenotypes of Staphylococcus aureus and enterococci, respectively. Tedizolid MIC >1 mg/L was reported for 3 S. aureus, 4 coagulase-negative staphylococci, and 2 enterococcal isolates; all streptococci were inhibited at MIC ≤0.5 mg/L. Tedizolid was ≥4-fold more potent than linezolid against all groups, including resistant phenotypes. Tedizolid had potent/stable activity against a large, contemporary collection of Gram-positive clinical isolates, with low rates of resistance.