In vitro activity of Oritavancin against gram-positive pathogens isolated in Canadian hospital laboratories from 2011 to 2015

- A synopsis of a 2011-2015 Canadian surveillance study of Gram-positive pathogens tested against the recently approved lipoglycopeptide oritavancin, and relevant comparative antimicrobial agents.
- 99.9% (2677/2680) of isolates of methicillin-susceptible Staphylococcus aureus (MSSA) and 99.7% (726/728) of isolates of methicillin-resistant S. aureus (MRSA) were susceptible to oritavancin (MIC, ≤0.12 μg/mL).
- All isolates of Streptococcus pyogenes (n = 218) and Streptococcus agalactiae (n = 269) were susceptible to oritavancin (MIC, ≤0.25 μg/mL).
- All isolates of vancomycin-susceptible Enterococcus faecalis (n = 508) were susceptible to oritavancin (MIC, ≤0.12 μg/mL).
- Oritavancin, dalbavancin, and telavancin demonstrated equivalent in vitro activities against MSSA (MIC90, 0.06 μg/mL; n = 602) and MRSA (MIC90, 0.06-0.12 μg/mL; n = 144) in 2015.

Gram-positive bacterial pathogens isolated from patient specimens submitted to 15 Canadian hospital laboratories from 2011 to 2015 were tested in the coordinating laboratory for susceptibility to oritavancin and comparative antimicrobial agents using the Clinical and Laboratory Standards Institute M07-A10 (2015) broth microdilution method. Oritavancin's in vitro activity was equivalent to, or more potent than, vancomycin, daptomycin, linezolid, and tigecycline against methicillin-susceptible Staphylococcus aureus (n = 2680; oritavancin MIC90, 0.12 μg/mL; 99.9% oritavancin-susceptible), methicillin-resistant S. aureus (n = 728; oritavancin MIC90, 0.12 μg/mL; 99.7% oritavancin-susceptible), Streptococcus pyogenes (n = 218; oritavancin MIC90, 0.25 μg/mL; 100% oritavancin-susceptible), Streptococcus agalactiae (n = 269; oritavancin MIC90, 0.12 μg/mL; 100% oritavancin-susceptible), and vancomycin-susceptible Enterococcus faecalis (n = 508; oritavancin MIC90, 0.06 μg/mL; 100% oritavancin-susceptible). Oritavancin, dalbavancin, and telavancin demonstrated equivalent in vitro activities (MIC90, μg/mL) against 602 isolates of MSSA (0.06, 0.06, 0.06, respectively) and 144 isolates of MRSA (0.12, 0.06, 0.06, respectively) collected in 2015.