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

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