Assessment of broth disk elution method for aztreonam in combination with ceftazidime/avibactam against <i>Enterobacterales</i> isolates

Infections caused by metallo-β-lactamase (MBL)-producing <i>Enterobacterales</i> are increasingly reported worldwide, and it is a significant challenge for clinical infection treatment. MBLs are adept at hydrolyzing almost all traditional β-lactam antibiotics except aztreonam, and the enzyme activity cannot be inhibited by traditional or novel β-lactamase inhibitors. The good thing is that the combination of aztreonam with ceftazidime/avibactam has been proven to be one of the potential therapeutic approaches for treating infections related with MBL-producing isolates. Broth microdilution (BMD) method is recommended as a reference method for its accuracy, but it is too complex to perform in most routine laboratories. Finding a more convenient, practical, and accurate susceptibility testing method for aztreonam/avibactam in clinical microbiology laboratories is very necessary. Here, we evaluated the performance of broth disk elution (BDE) method for aztreonam in combination with ceftazidime/avibactam against <i>Enterobacterales</i> isolates, with BMD as a reference.