Spectrum and potency of dalbavancin tested against 3322 Gram-positive cocci isolated in the United States Surveillance Program (2004)

Dalbavancin is an injectable, next generation lipoglycopeptide with an extended serum elimination half-life. Once-weekly dosing has been successful for treatment of skin and skin structure (SSSI) and catheter-related bloodstream infections (CR-BSI). Concurrent with clinical trails, dalbavancin resistance surveillance was initiated in 2003, and results are reported here for the 2004 United States (USA) component. A total of 3322 Gram-positive cocci were tested by reference broth microdilution methods. Organism species tested included: Staphylococcus aureus (2102; 49% oxacillin-resistant), coagulase-negative staphylococci (CoNS; 255, 82% oxacillin-resistant), β-hemolytic streptococci (241), viridans group streptococci (46), and Streptococcus pneumoniae (678). Dalbavancin (MIC90,0.06–0.12 μg/mL) was comparable in spectrum, but superior in potency to vancomycin (MIC90,1–2 μg/mL) against staphylococci. Dalbavancin MIC90 values against the tested streptococci was 0.03 μg/mL. Dalbavancin was more active against tested SSTI pathogens than comparator agents having complete susceptibility rates (100.0%) similar to vancomycin. Vancomycin, (16- to 32-fold), linezolid (8- to 32-fold), daptomycin (4- to 32-fold), and quinupristin/dalfopristin (4- to 32-fold) were less active than dalbavancin. In conclusion, dalbavancin exhibited greater potency than comparison glycopeptides or lipopeptides, streptogramin combinations, and oxazolidinones against Gram-positive pathogens associated with SSSI or CR-BSI. Dalbavancin wild-type MIC distributions remain unchanged compared with prior sampled years (2002–2003) in the USA.