Comparative evaluation of practical in-vitro methods for testing synergy between ceftazidime-avibactam and aztreonam against metallo-β-lactamase and serine carbapenemase-producing Enterobacterales species

The combination of CZA and ATM demonstrated significant synergistic results in MBL and serine carbapenemase-producing Enterobacterales species. The disk replacement and inverse D-zone methods are feasible and cost-effective for CZA and ATM synergy testing in routine AST within resource-limited settings, guiding treatment decisions.