How a gene turns a bug into a superbug -- and what to do about it

There's been a lot of talk recently about NDM-1, a gene that gives many bacteria a weapon against carbapenems, an important class of antibiotics. Because many of these bacteria are already resistant to other classes of antibiotics, NDM-1 renders them immune to almost anything we throw at them. This is bad news indeed.

NDM-1 has been found in India and Pakistan mainly, but cases are popping up in Britain and other nations in which a lot of people travel to and from that part of the world. Last month, researchers detailed the emergence of NDM-1 in a paper published in the Lancet.

In the U.S., three cases have been confirmed, in California, Illinois and Massachusetts. Researchers believe all three patients picked up the resistant bug in hospitals in India. So what to do?

At least one renowned bacteria researcher, Dr. Patrice Nordmann, said Tuesday that it is possible for nations to slow the spread in their own populations simply by screening patients who are transferred from foreign hospitals.

Nordmann expressed similar sentiments last week at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Boston.

Practically, this means isolating patients who are transferred from, say, a hospital in New Delhi, for 48 hours while they are screened for NDM-1 bacteria, said Nordmann, who is chief of the Department of Bacteriology-Virology at Bicetre Hospital outside Paris.

Then hospital staff can act accordingly — taking extra precautions in caring for the patient, keeping the patient isolated from others and treating the infection.

French hospitals are already beginning to do this, he said. For France, a nation of about 65 million people, that means screening approximately 10,000 patients a year, he said. There is even talk of screening every resident of France who had been treated in a foreign hospital over the last year, he said.

Other nations, from Japan to Singapore, are also considering screening, he said. The U.S. does not have a policy yet, he said.

Countries such as Denmark and Netherlands have used the screening technique, along with other measures, to slow the spread of methicillin-resistant Staphylococcus aureus, or  MRSA. Screening is an opportunity to get ahead of the situation, especially because no new drugs are in development to combat NDM-1-armed bacteria, Nordmann said.

"This should be done immediately worldwide,” Nordmann said at the meeting. “We should not wait six months.”

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