What is this new "Superbug"?

Luke Chen, MD

A new type transferable antibiotic resistance in gram-negative organisms. NDM-1 (New Delhi Metallo-beta-lactamase 1) is named after the city that was visited by the patient in whom the first organism carrying this enzyme was isolated. NDM-1 is a new type of plasmid-mediated resistance that can hydrolyze all beta-lactams, carbapenems but generally not monobactams (e.g. aztreonam).  The plasmid can concurrently carry other resistance-conferring genes and can be transferred between types of gram-negative bacteria.

The NDM-1 resistance is detectable using current CLSI recommendations and the modified-Hodge test. Patients suspected or shown to have this type of drug resistance should be isolated with contact precaution and have strict hand hygiene with approved products.  So far, this resistance is not widespread.