Linezolid displays potent antibacterial activity against a variety of multidrug-resistant gram-positive microbes in vitro and in vivo, including streptococcus and methicillin-resistant Staphylococcus aureus (MRSA). Linezolid has shown excellent efficacy against gram-positive cocci, including Staphylococcus aureus, coagulase-negative staphylococci, enterococci, and streptococci, with MICs ranging from 0.5 to 4µg/ml. Linezolid is a potent inhibitor of cell-free transcription-translation in E. coli, exhibiting 50% inhibitory concentrations (IC50s) of 1.8µM. The drug works by inhibiting the initiation of bacterial protein synthesis and has excellent bioavailability in animal studies.