- Last Update On : 2013-02-27
Recently, the CDC reported that a new type of multi-drug resistant organism (MDRO) has been detected in the United States (MMWR 2010; 59:750). Three isolates of enteric gram negative bacilli, from 3 different states have been found to produce an enzyme called New Delhi metallo-beta-lactamase (NDM-1). This enzyme confers resistance to all beta-lactam anti-microbials, including carbapenems. The three organisms identified to date included an Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae. All were isolated from patients who recently received medical care in India. These organisms were resistant to most other anti-microbials as well, including aztreonam. Carbapenem resistance of the NDM-1 type is detected by standard susceptibility test methods. Laboratories perform 3 different types of susceptibility testing on any enteric isolate suspicious for carbapenem resistance. Enteric organisms suspicious for NDM-1 are forwarded to the CDC for confirmation. Physicians should be aware of the possibility of NDM-1 producing organisms in patients who have received medical care in India or Pakistan in the last 6 months. Evolution of antibiotic resistant bacteria continues to outpace the development of new antibiotics.