Detection of NDM-19, a novel variant of the New Delhi metallo-β-lactamase with increased carbapenemase activity under zinc-limited conditions, in Switzerland

A novel New Delhi metallo-β-lactamase (NDM) variant, NDM-19, was identified in a carbapenem-resistant E. coli strain isolated from a subcutaneous infection of a laparotomy scar from an Egyptian patient in a Swiss hospital. NDM-19 is a derivative of NDM-7, from which it differs by a single amino acid substitution (Ala233Val). Under zinc-limiting growth conditions, E. coli DH5α transformants producing NDM-19 displayed reduced susceptibility towards expanded-spectrum cephalosporins and carbapenems as compared to transformants producing NDM-1 or NDM-7