Antimicrobial Activity of the Investigational Pleuromutilin Compound BC-3781 Tested against Gram-Positive Organisms Commonly Associated with Acute Bacterial Skin and Skin Structure Infections

BC-3781 is a novel semisynthetic pleuromutilin antimicrobial agent developed as an intravenous and oral therapy for acute bacterial skin and skin structure infections (ABSSSI) and respiratory tract infections (RTI). BC-3781 and comparator agents were tested by the broth microdilution method against 1,893 clinical Gram-positive organisms predominantly causing ABSSSI. BC-3781 exhibited potent activity against methicillin-resistant Staphylococcus aureus (MIC(50/90), 0.12/0.25 μg/ml), coagulase-negative staphylococci (MIC(50/90), 0.06/0.12 μg/ml), β-hemolytic streptococci (MIC(50/90), 0.03/0.06 μg/ml), viridans group streptococci (MIC(50/90), 0.12/0.5 μg/ml), and Enterococcus faecium (including vancomycin-nonsusceptible strains) (MIC(50/90), 0.12/2 μg/ml). Compared with other antibiotics in use for the treatment of ABSSSI, BC-3781 displayed the lowest MICs and only a minimal potential for cross-resistance with other antimicrobial classes.