Comparative in vitro efficacy of aztreonam-avibactam and other alternatives (cefepime-taniborbactam, cefepime-zidebactam, and cefiderocol) against metallo-β-lactamase-producing Enterobacterales isolated in 2024 in France.

We evaluated the in vitro activity of aztreonam-avibactam and other agents against 593 metallo-β-lactamase (MBL)-producing Enterobacterales collected in France in 2024. Aztreonam-avibactam showed the highest activity (98% susceptible), with resistance mainly observed in NDM-5-producing Escherichia coli belonging to ST167, ST405, and ST361. Cefepime-zidebactam also exhibited strong activity (96.6% of susceptibility). Cefepime-taniborbactam and cefiderocol showed reduced overall activity (76.4% and 74.9% susceptibility, respectively), with reduced efficacy mainly observed among NDM-producing isolates. Comparison with 1,465 isolates from 2023 showed no increase in aztreonam-avibactam resistance.