Yesterday, the CDC reported through its Morbidity and Mortality Weekly Report that the superbug NDM-1 (New Delhi metallo-beta-lactamase 1), which was first identified in patients two years ago, had been discovered in 13 patients in the USA alone, including two in which the infection spread within the same hospital.
A Rhode Island woman, who was born in Cambodia, returned to Southeast Asia for a visit in May 2011. While she was there, she was diagnosed with spinal cord compression in December 2011 and hospitalized in Ho Chi Minh City. She was back in the USA in January 2012, but hospitalized again and diagnosed with lymphoma. By February, it became apparent that she was carrying highly resistant bacteria in her bladder.
In March, a sample of Klebsiella pneumoniae from her urine was found to contain NDM-1. She was discharged on March 26. Four days later, one of the seven other patients in the hematology/oncology unit was found to be carrying NDM-1 as well. The CDC confirmed that it was the same strain.
NDM-1 is extremely drug-resistant and it responds to the drugs colistin and tigecycline, both in varying effectiveness. While the CDC report does not include a conclusion on how the actual transmission occurred, the two patients were cared for by different physicians and nurse practitioners, and stayed in different rooms. The first patient was allowed to walk the floor, before she was put in quarantine, implying that this could have been a vector of transmission.