activity of omadacycline against clinical isolates of .

Nocardiosis typically requires a prolonged treatment duration of ≥6 months and initial combination therapy with 2-3 antibiotics. First-line regimens for nocardiosis are associated with considerable toxicity; therefore, alternative therapies are needed. Omadacycline is an aminomethylcycline with broad antimicrobial activity whose activity against species has not been formally assessed. The potency of omadacycline was evaluated against 300 clinical isolates by broth microdilution. The most common species tested were (21%), (20%), and (12%). The most common specimens were respiratory (178 isolates, 59%) and wound (57 isolates, 19%). Omadacycline minimum inhibitory concentrations (MICs) across all species ranged from 0.06 µg/mL to 8 µg/mL, with an MIC of 2 µg/mL and MIC of 4 µg/mL. The lowest MICs were found among (MIC = 0.25 µg/mL, MIC = 0.25 µg/mL), (MIC = 0.25 µg/mL, MIC = 1 µg/mL), complex (MIC = 0.5 µg/mL, MIC = 1 µg/mL), (MIC = 0.5 µg/mL, MIC = 2 µg/mL), and (MIC = 1 µg/mL, MIC = 2 µg/mL). The highest MICs were found among (MIC = 4 µg/mL, MIC = 8 µg/mL). potency differed by species among clinical isolates. Further studies are warranted to evaluate the potential clinical utility of omadacycline for nocardiosis.