New strains of bacteria with the ability to resist even the strongest antibiotics have emerged in India and spread worldwide, including to Canada, researchers warn.
British scientists have discovered bacteria that are able to make an enzyme called NDM-1, or New Delhi metallo-beta-lactamase 1.
Genes enable the bacteria to make the enzyme so they can flourish even in the presence of nearly all known antibiotics.
"I think we should be very worried that the value of antibiotics is being eroded," said study author Dr. David Livermore.
The strains have been found in 180 people in India, Pakistan and the U.K. At least 17 of these had a history of travelling to India or Pakistan, Livermore and his co-authors said in Wednesday's issue of the journal Lancet Infectious Diseases.
NDM-1 has been seen largely in E. coli bacteria, the most common cause of urinary tract infections outside of hospitals. The gene for the enzyme is found on DNA structures known as plasmids that can be easily copied and passed on to other types of bacteria.
Antibiotic-resistant E. coli can cause fatal pneumonia and other infections.
"The potential for wider international spread of producers and for NDM-1-encoding plasmids to become endemic worldwide, are clear and frightening," the study's authors concluded.
NDM-1 cases discovered:
United Kingdom: 37
Chennai, India: 44
Haryana, India: 26
Other sites in India and Pakistan: 73
Source: The Lancet Infectious Diseases
"The spread of these multi-resistant bacteria merits very close monitoring," agreed Johann Pitout, of the division of microbiology at the University of Calgary, in an accompanying commentary.
Pitout called for internationally funded surveillance of the superbug strain, particularly in countries that actively promote medical tourism.
"The consequences will be serious if family doctors have to treat infections caused by these multi-resistant bacteria on a daily basis," he said.
Still, doctors say there isn't anything the public at large needs to worry about. Antibiotic resistance doesn't mean the superbugs are indestructible, and the bacteria continue to be killed by standard disinfectants, Livermore noted.
The U.K. Health Protection Agency has issued an alert about the resistant bacteria, requiring doctors there to report all suspected cases.
"The threat comes from the fact that these bacteria are so resistant," said Livermore, who is also a spokesman for the U.K. agency.
"Nowadays, we have five or six good antibiotics that are active in more or less all infections," said Livermore, who specializes in infectious diseases. "Here, we're down to one or two not-very-good, rather old antibiotics."
The researchers said the resistant bacteria appeared to be already circulating widely in India, where the health system is much less likely to identify the presence of the NDM-1 enzyme or have adequate antibiotics to treat patients.
Cases in Alberta, Vancouver
NDM-1 has also been detected in Australia, Canada, the Netherlands, the U.S. and Sweden, according to the journal articles, though no figures were given.
One Canadian case occurred in Vancouver in February, said Dr. Howard Njoo, director general of the Centre for Communicable Diseases and Infection Control at the Public Health Agency of Canada.
The patient picked up the infection in India where the hospital used appropriate measures and it didn't spread, Njoo said. The individual recovered.
Pitout identified a second case in Alberta where the patient had been in hospital in India, and fell ill upon returning home.
The researchers said that since many Americans and Europeans travel to India and Pakistan for elective procedures like cosmetic surgery, it was likely the new strain would spread worldwide.
Scientists note this hasn't actually happened, but they are raising an alarm about the potential threat.
It is significant that this new resistance is occurring in common bacteria we all carry like E. coli, said Dr. Andrew Simor, chief of microbiology and infectious diseases at Toronto's Sunnybrook Hospital.
Three steps are needed to stop it, Simor said:
- Adequate surveillance to detect it early and track it.
- Appropriate use of antibiotics.
- Appropriate and meticulous infection control in health-care facilities, such as handwashing and proper disinfection of equipment.
NDM-1 was added to Canada's national hospital surveillance system in September 2009, the agency said.
NDM-1 is an enzyme, not a gene or bacterium as originally reported.Aug 11, 2010 11:25 AM ET