Summary of linezolid activity and resistance mechanisms detected during the 2012 LEADER surveillance program for the United States.

This study summarizes the linezolid susceptibility testing results for 7,429 Gram-positive pathogens from 60 U.S. sites collected during the 2012 sampling year for the LEADER Program. Linezolid showed potent activity when tested against 2,980 Staphylococcus aureus isolates, inhibiting all but 3 at ≤2 μg/ml. Similarly, linezolid showed coverage against 99.5% of enterococci, as well as for all streptococci tested. These results confirm a long record of linezolid activity against U.S. Gram-positive isolates since regulatory approval in 2000.