In vitro activity of omadacycline against bacterial isolates from bone/joint infections and rare pathogens in the SENTRY antimicrobial surveillance program (2015–2023)

Objectives: Omadacycline is an aminomethylcycline (tetracycline class) antibacterial approved by the United States Food and Drug Administration (2018) for treatment of adults with acute bacterial skin and skin structure infection (ABSSSI) and community acquired bacterial pneumonia (CABP) caused by indicated organisms (oral and iv formulations). Omadacycline has activity against bacterial isolates expressing common tetracycline resistance mechanisms (ribosomal protection proteins and efflux pumps), which render older generation tetracyclines inactive. Omadacycline in vitro activity was assessed against 919 bacterial isolates collected from patients with bone/joint infections in the United States and Europe (2015–2023) and 3945 rarely encountered bacterial pathogens from patients (multiple infection sites) in the United States (2015–2023) as part of the SENTRY Antimicrobial Surveillance Program. program. Methods: Broth microdilution susceptibility testing followed Clinical and Laboratory Standards Institute M07 (2024) and M100 (2024) guidelines. Results: Omadacycline demonstrated susceptibilities of ≥90.0% (FDA breakpoints) against Staphylococcus aureus (including MRSA), Staphylococcus lugdunensis, Enterococcus faecalis (including vancomycin-resistant), and streptococci including Streptococcus anginosus, Streptococcus pneumoniae, and Streptococcus pyogenes from patient with bone/joint infections. Omadacycline demonstrated potent in vitro activity against rare Gram-positive pathogens (multiple infection sites), inhibiting 97.3%, 91.3%, and 99.4% of uncommon staphylococci, streptococci, and enterococci isolates at or below current FDA approved ABSSSI breakpoints for S. aureus, S. pyogenes, and E. faecalis. Conclusions: The potent omadacycline activity observed in this study suggests potential clinical utility for treatment of bone/joint infections and rarely encountered Gram-positive infections caused by various staphylococci, streptococci, and enterococci isolates and supports ongoing clinical trials for these disease indications.