Surveillance of Omadacycline Activity Tested against Clinical Isolates from the United States and Europe: Report from the SENTRY Antimicrobial Surveillance Program, 2016 to 2018.

Omadacycline is a broad-spectrum aminomethylcycline approved in October 2018 by the U.S. Food and Drug Administration for treating acute bacterial skin and skin structure infections and community-acquired pneumonia as both an oral and intravenous once-daily formulation. In this report, the activities of omadacycline and comparators were tested against 49,000 nonduplicate bacterial isolates collected prospectively during 2016 to 2018 from medical centers in Europe (24,500 isolates, 40 medical centers [19 countries]) and the United States (24,500 isolates, 33 medical centers [23 states and all 9 U.S. census divisions]). Omadacycline was tested by broth microdilution following the methods in Clinical and Laboratory Standards Institute document M07 (, 11th ed., 2018). Omadacycline (MIC, 0.12/0.25 mg/liter) inhibited 98.6% of isolates at ≤0.5 mg/liter, including 96.3% of methicillin-resistant isolates and 99.8% of methicillin-susceptible isolates. Omadacycline potency was comparable for (MIC, 0.06/0.12 mg/liter), viridans group streptococci (MIC, 0.06/0.12 mg/liter), and beta-hemolytic streptococci (MIC, 0.12/0.25 mg/liter), regardless of species and susceptibility to penicillin, macrolides, or tetracycline. Omadacycline was active against all tested (MIC, 1/8 mg/liter; 87.5% of isolates were inhibited at ≤4 mg/liter) except (MIC, 16/>32 mg/liter) and indole-positive spp. (MIC, 8/32 mg/liter) and was most active against (MIC, 0.5/2 mg/liter), (MIC, 1/2 mg/liter), and spp. (MIC, 1/4 mg/liter). Omadacycline inhibited 92.4% of species complex and 88.5% of isolates at ≤4 mg/liter. Omadacycline was active against (MIC, 0.5/1 mg/liter), regardless of β-lactamase status, and against (MIC, ≤0.12/0.25 mg/liter). The potent activity of omadacycline against Gram-positive and -negative bacteria indicates that omadacycline merits further study in serious infections in which multidrug resistance and mixed Gram-positive and Gram-negative bacterial infections may be a concern.