Extremely Drug-Resistant Infections Spreading Fast
Common Bacteria Are Picking Up New Antibiotic-Resistant Gene
July 10, 2010 -- Is this the beginning of the end of the antibiotic era?
NDM, a gene that makes germs impervious to many antibiotics, is spreading worldwide among bacteria in the gut that most commonly cause infections. The gene lives on a DNA strand called a plasmid that is easily swapped among different species of harmful gut bacteria.
The gene evolved in India -- NDM stands for New Delhi metallo-beta-lactamase -- but is widespread in Pakistan and Bangladesh as well. It's been isolated all across the U.K., prompting a national alert. It's also popped up in the U.S., Canada, Sweden, Australia, and the Netherlands.
The bad news comes from a sobering report by Timothy R. Walsh, PhD, professor of infection, immunity, and biochemistry at Wales' Cardiff University, and colleagues.
"This heralds a new and darker dawn in infections," Walsh tells WebMD. "If we looked in India a few years ago we would not have seen this. But in three or four years it has gone into 1% to 4% of the [gut] bacteria population in India. That is incredible. It came from nowhere."
NDM Superbugs Spreading Fast?
There's even worse news. Nearly all highly resistant bugs pop up only in hospitals. But gut bacteria carrying the NDM gene are spreading throughout affected communities.
"There are lots of people carrying this resistance," Walsh says. "The crux of the matter is that when bugs ... acquire this type of gene they become resistant to all beta-lactams. And beta-lactams like penicillin are the main therapies to treat these infections with."
You don't have to be a microbiologist to know the bugs Walsh is talking about. One is E. coli. Another is Klebsiella pneumoniae, a common cause of pneumonia. Both kinds of infection can be deadly.
There could be "serious consequences," says Johann D.D. Pitout, MD, professor of pathology and laboratory medicine at Canada's University of Calgary, in an editorial accompanying the Walsh report in the Aug. 11 online issue of The Lancet.
"The potential is there for a major issue: that we would have common infections, like urinary tract infections, caused by drug-resistant organisms," Pitout tells WebMD. "It is a huge surprise to see it spread all over the subcontinent. It looks like it is a really rapid spread. It is too early to tell. But it sure as hell is widespread and that is very worrying."
In the U.S., the CDC last June reported three cases of NDM bacteria isolated from U.S. patients. All of the patients were of Indian descent, and all had undergone medical procedures while visiting India for other reasons.
Are there more U.S. cases? Nobody knows, because nobody has looked very hard, says Brandi Limbago, PhD, the CDC team leader for antimicrobial resistance and characterization.
"In this country we do not have a sense of the prevalence at all. That is a concern to me, at least," Limbago tells WebMD. "The rate it is spreading in the U.K. is concerning. We don't have info on the U.S. I don't know if we should be terrified or moderately worried."