http://www.medicinenet.com/ndm-1/article.htm

NDM-1 stands for New Delhi metallo-beta-lactamase, which is an enzyme produced by certain strains of bacteria that have recently acquired the genetic ability to make this compound. The enzyme is active against other compounds that contain a chemical structure known as a beta-lactam ring. Unfortunately, many antibiotics contain this ring, including the penicillins, cephalosporins, and the carbapenems.