Emergence of New Delhi Metallo-β-Lactamase, Austria

To the Editor: Extended-spectrum β-lactamase–producing Enter-obacteriaceae strains have emerged as a major public health problem throughout the world, particularly in India and Pakistan. The widespread use of carbapenems, the only agents reliably active against these bacteria, resulted in the emergence of a new resistance mechanism. New Delhi metallo-β-lactamase (NDM-1) was fi rst detected in a Klebsiella pneumoniae isolate in 2008 from a Swedish patient of Indian origin; it has since been reported in increasing numbers of infections in patients from India, Pakistan, and the United Kingdom (1–3). NDM-1 shares very little identity with other metallo-β-lactamase enzymes; Enterobacteriaceae isolates with NDM-1 show high resistance to nearly all commonly used antibacte-rial agents (4). Most NDM-1 patients in Europe and the United States had received medical care in India or Pakistan before isolation of the strain. However, the emergence of NDM-1 poses the risk of plasmid-mediated transfer of the carbapenemase enzyme bla NDM-1 between different bacterial strains, which could lead to serious public health issues (3,5). We report the emergence of NDM-1–positive K.