J Glob Antimicrob Resist 2019 Feb 27. Epub 2019 Feb 27.
JMI Laboratories, North Liberty, IA, United States.
Objectives: Omadacycline is an aminomethylcycline antibacterial (oral and intravenous once-daily formulation) that recently (October 2018) received FDA approval for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and community-acquired bacterial pneumonia (CABP) against selected organism groups. In this study, omadacycline and comparators were tested against 14000 non-duplicate bacterial isolates collected prospectively during 2017 from medical centres in Europe (EUR; 7000 isolates) and the United States (USA; 7000 isolates).
Methods: Omadacycline was tested by broth microdilution following CLSI M07-A11 (2018) methods.
Results: A total of 98.7% ofStaphylococcus aureus isolates were susceptible (S) to omadacycline (MIC, 0.12/0.25 mg/L; ABSSSI breakpoints) including 96.5% of MRSA, 99.8% of MSSA, and 93.9% of tetracycline-resistant strains. Omadacycline activity was similar for Streptococcus pneumoniae (MIC 0.06/0.12 mg/L; 98.6%S [CABP breakpoints]), Streptococcus anginosus group (MIC 0.06/0.06 mg/L; 100.0%S [ABSSSI breakpoints]), and Streptococcus pyogenes (MIC 0.06/0.12 mg/L; 97.7%S [ABSSSI breakpoints]). Omadacycline demonstrated activity against Enterobacter cloacae species complex isolates (MIC, 2/4 mg/L; 91.2%S [ABSSSI breakpoints]), Klebsiella pneumoniae (MIC, 2/8 mg/L; 87.5%S [CABP and ABSSSI breakpoints]), and inhibited 99.1% of Escherichia coli (MIC, 0.5/2 mg/L) isolates at ≤4 mg/L. Omadacycline was active against Haemophilus influenzae (MIC, 0.5/1 mg/L; 99.8%S [CABP breakpoints]) including all β-lactamase positive isolates and inhibited 100.0% of Moraxella catarrhalis isolates at ≤0.25 mg/L.
Conclusions: The potent activity of omadacycline against Gram-positive and Gram-negative bacteria indicates that omadacycline merits further study in serious infections in which multidrug resistance and mixed Gram-positive and Gram-negative infections may be a concern.