Sensitive and specific phenotypic assay for metallo-beta-lactamase detection in Enterobacteria by use of a moxalactam disk supplemented with EDTA

Moxalactam is highly hydrolyzed by plasmid-mediated metallo-β-lactamases (MBLs), whereas it is poorly inactivated by serine-active carbapenemases. This study demonstrated that moxalactam resistance constituted an effective screen for MBL expression in enterobacteria, which could be confirmed, even in low-MBL-producing isolates, by a disk potentiation test using moxalactam and EDTA.