New Delhi Metallo-β-lactamase (NDM) is a zinc-dependent (class B) metallo-β-lactamase enzyme produced by certain Gram-negative bacteria, most commonly members of the Enterobacterales family, such as Klebsiella pneumoniae and Escherichia coli.
NDM hydrolyzes (inactivates) a broad spectrum of β-lactam antibiotics, including penicillins, cephalosporins, and crucially the carbapenems, which are often used as last-resort treatments for severe bacterial infections. As a result, bacteria producing NDM are resistant to many of the most important β-lactam antibiotics.
The genetic determinant encoding the NDM gene is often located on a plasmid, facilitating horizontal gene transfer and allowing resistance to spread rapidly within and between bacterial species.