In vitro activity of omadacycline against geographically diverse rapidly growing nontuberculous mycobacteria (NTM) clinical isolates

• Treatment options for NTM disease are limited. • Omadacycline was assessed in vitro against RGM clinical isolates from 15 countries. • Omadacycline demonstrated potent in vitro activity against all RGM species tested. • Resistance was observed to all comparator agents tested, except for amikacin. • Omadacycline is a potential treatment option for NTM, e.g. M. abscessus species. Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens with limited treatment options due to resistance to multiple antibiotic classes. This study aimed to evaluate the in vitro activity of omadacycline and comparator antibiotics against rapidly growing mycobacteria (RGM) clinical isolates. Minimum inhibitory concentration (MIC) evaluation of RGM clinical isolates was performed by two independent laboratories (EU and Japan). A total of 383 isolates (211 EU, 172 Japan) were evaluated. Omadacycline was active against all RGM species tested. For Mycobacterium abscessus subsp. abscessus , MIC 50 and MIC 90 values (read at 100 % inhibition) were 1 and 4 µg/mL (EU) and 0.5 and 1 µg/mL (Japan), respectively. Mycobacterium fortuitum and Mycobacterium chelonae both had MIC 90 values of 0.5 µg/mL (Japan). Omadacycline has consistent, potent in vitro activity against RGM clinical isolates from 15 geographically diverse countries, and thus warrants additional studies and continued development of omadacycline as a potential treatment option for NTM-related disease.