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

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, MIC₅₀ and MIC₉₀ 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 MIC₉₀ 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.