Metallo-β-lactamases (MβLs) production in gram negative bacilli is an emerging health problem worldwide. We aimed to determine the occurrence of MβLs among gram negative bacilli (GNB) by phenotypic and genotypic methods in Mansoura University hospital, Egypt. We conducted a prospective study on 107 GNB isolates recovered from different clinical specimens collected from different patients. Species identification and antibiotic susceptibility profile was determined by MicroScan Wa1kAway system. GNB which showed resistance to imipenem and/or meropenem were screened for MBL production by double-disk synergy test (DDST). | Phenotypic detection and genotypic characterization of metallo-betalactamases in gram negative bacilli isolated from mansoura university hospital in Egypt