Identified Gene May Bring on New Superbug

Aug. 11, 2010 — -- Some British patients who underwent plastic surgery in South Asia were infected with a bacteria carrying a specialized gene that has the potential to turn almost any other bacteria into an antibiotic-resistant bug, according to an article published today in the journal Lancet Infectious Diseases.

The so-called superbug gene has so far been identified in 37 people who returned to Great Britain after undergoing surgery in India or Pakistan, researchers said.

British researchers reported that the new gene, called NDM-1, can be easily be transferred into common bacteria such as E. Coli, according to the article. The gene alters bacteria, making them resistant to nearly all known antibiotics.

"Most of modern medicine is based on the notion that antibiotics will work. If you no longer knew antibiotics worked, you couldn't do as much surgery, chemotherapy, transplantation," said Dr. Martin Blaser, chairman of the department of medicine at New York University Langone Medical Center. "Antibiotics are part of the foundation of modern medical care."

The drug resistannce is spread by plasmids, genetic material that can hop from one organism to another and are then free to reproduce and share resistance with other bacteria. Even the most powerful antibiotics are unable to treat these infections.

Researchers have already identified bacteria susceptible to the NDM-1 superbug gene in people living in the U.S., Netherlands, Australia, and Canada who have traveled to India for medical care, according to the accompanying editorial.

"We've been dealing with antibiotic resistant gene determinants coming from overseas for some time," said Dr. Christopher Ohl, associate professor of infectious disease at Wake Forest University Baptist Medical Center. Researchers said the popular medical tourism industries in India and Pakistan could fuel a surge in antibiotic resistance, as patients import dangerous bugs back to their home countries.

Medical tourism is just one of many conduits to transmit superbugs. Importing foods and travelling while sick have contributed for other superbug infections such as MRSA and drug resistant tuberculosis, said Dr. Larry Baddour, chair of the division of infectious disease at Mayo Clinic in Rochester, Minn.

"What's happening in India and Pakistan is important, but it's the second verse of the same song so to speak," said Baddour. "This is what we've been seeing globally over time."

Superbugs: 'Slow Motion Doom and Gloom,' Experts Says

The overuse of antibiotics has contributed to the increase in antibiotic resistant bugs. Over time, bacteria grow stronger than the treatments they may be regularly exposed to. And, according to many experts, there's no end in sight.

"It's slow motion doom and gloom," said Baddour. "We are feeling the limited availability of active antibiotics, and we're put in situations where we don't have active therapies to treat cases."

Although researchers are not able to reverse the superbug genes, it is possible to slow the spread of superbugs, according to Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center.

"Antibiotics are used when they don't have to be used, and are continued for too long," said Schaffner.

Appropriate use of antibiotics, known as antibiotic stewardship, can keep new bugs from spreading, said Schaffner.

"Make sure every use of antibiotic is necessary and discontinue when no longer needed," he said.

Baddour said that over 70 years of exposure to some of the same types of antibiotics has given bacteria the time to develop resistant genes.

"The bacteria are getting smarter and smarter and they're gaining mechanisms to get around the antibiotics," said Baddour. "We need newer agents."

Research is slim on developing stronger forms of antibiotics. In fact, according to Schaffner, many pharmaceutical manufacturers have stopped research on antibiotics mainly because of the economics.

"Antibiotics are given to a small group of people for a short amount of time," said Schaffner. "And, I don't know of any other product that when it comes out on the market, experts will say 'don't use it' unless you need it, of course."

Still, while government agencies like the Centers for Disease Control and Prevention work to promote campaigns for antibiotic stewardship, it may be another decade before researchers develop usable drugs, he said.

"The problem is that the microbes are acquiring resistance faster than we're developing new drugs to combat the microbes," said Blaser. "So we are in a race, and we are losing ground."