activity of meropenem-vaborbactam plus aztreonam against metallo-β-lactamase-producing .

We evaluated the activity of meropenem-vaborbactam plus aztreonam (MEV-ATM) against 140 metallo-β-lactamase (MBL)-producing isolates. Among them, 25 isolates (17.9%) displayed minimum inhibitory concentrations (MIC) ≥ 8 µg/mL, while 112 (80.0%) had MIC ≤ 2 µg/mL. Genomic analysis and subsequent gene cloning experiments revealed OmpK36 134-135GD-insertion and increased carbapenemase gene ( and ) copy numbers are the main factors responsible for MEV-ATM non-susceptibility. Notably, MEV-ATM is actively against aztreonam-avibactam-resistant mutants due to CMY-16 mutations.