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

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