New Delhi metallo-β-lactamase (NDM-1): an update

New Delhi metallo-β-lactamase (NDM-1) is a novel broad spectrum carbapenemase with ability to inactivate all β-lactams except aztreonam. However, most of the NDM-1-producers also produce aztreonam hydrolysing-β-lactamases thereby making these pathogens absolutely resistant to all β-lactams. The bla(NDM-1) gene encodes a 27.5 kDa protein of 269 amino acids. It shares very little identity with other metallo-β-lactamases. Maximum identity has been observed to VIM-1/VIM-2 (32.4%). This mini-review is an update of the scientific literature for the said enzyme. Following the recommendation of David livermore, we further propose to combine "aztreonam" and "inhibitor of the most frequently encountered aztreonam hydrolysing-β-lactamases in a given setting" as a possible strategy against NDM-1-producers. The inhibitor should be 'versatile' as well, i.e. it should have the ability to inhibit most of the variants of aztreonam hydrolysing-β-lactamases prevalent in the concerned setting. We strongly recommend surveillance studies using aztreonam/NXL-104-combination against NDM-1-producing pathogens in different geographical regions across the globe.