New -Lactamase Inhibitors Nacubactam and Zidebactam Improve the in Vitro Activity of -Lactam Antibiotics against Mycobacterium abscessus Complex Clinical Isolates

The new diazabicyclooctane-based -lactamase inhibitors avibactam and relebactam improve the in vitro activity of -lactam antibiotics against bacteria of the Mycobacterium abscessus complex (MABC). Here, we evaluated the in vitro activities of two newer diazabicyclooctane-based -lactamase inhibitors in clinical development, nacubactam and zidebactam, with -lactams against clinical isolates of MABC. Both inhibitors lowered the MICs of their partner -lactams, meropenem (8-fold) and cefepime (2-fold), respectively, and those of other -lactams, similar to prior results with avibactam and relebactam.