Triple antimicrobial combinations with potent synergistic activity against M. abscessus

Synergy of antimicrobial combinations was tested against contemporary Mycobacteroides abscessus isolates using 2-D and 3-D checkerboard assays. Triple combinations of omadacycline-azithromycin-clofazimine, tigecycline-azithromycin-clofazimine, omadacycline-azithromycin-linezolid and omadacycline-azithromycin-contezolid demonstrated synergy (FIC [≤] 0.5) against 33%, 31%, 62%, and 66% of isolates, respectively. Notably, in all triple combinations, macrolide resistant M. abscessus subsp. abscessus and M. abscessus subsp. bolletii isolates were fully sensitized to azithromycin at the FIC index, as were isolates with elevated clofazimine MICs.