The objective of this study was to test the efficacy of an inhibitor of the New Delhi metallo-β- lactamase (NDM-1). Inhibiting expression of this type of antibiotic-resistance gene has the potential to restore antibiotic susceptibility in all bacteria carrying the gene.Methods: We have constructed a peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) that selectively inhibits the expression of NDM-1 and examined its ability to restore susceptibility to meropenem in vitro and in vivo.Results:In vitro, the PPMO reduced the MIC of meropenem for three different genera of pathogens that express NDM-1. In a murine model of lethal E. coli sepsis, the PPMO improved survival (92%) and reduced systemic bacterial burden when given concomitantly with meropenem.Conclusions: These data show that a PPMO can restore antibiotic susceptibility in vitro and in vivo and that the combination of PPMO and meropenem may have therapeutic potential against certain class B carbapenem- resistant infections in multiple genera of Gram-negative pathogens
