In vitro pharmacokinetics/pharmacodynamics of the combination of avibactam and aztreonam against MDR organisms.

Objectives: The combination of aztreonam and avibactam has been proposed for the treatment of infections caused by metallo-β-lactamase-producing Gram-negative organisms, given the stability of aztreonam against metallo-β-lactamases plus the broad coverage of avibactam against AmpC β-lactamases and ESBLs. This study aimed to evaluate the efficacy of the combination against four clinical isolates with defined but diverse β-lactamase profiles.

Methods: The MICs of aztreonam were determined without and with avibactam (1, 2, 4, 8 and 16 mg/L).