A hospital pathogen first identified in India two years ago has now emerged in New Delhi’s water supplies. Faced with a dwindling drug arsenal, scientists and public health officials are calling for new antimicrobial medicines and prudent use of existing drugs to help curb the rise of the rapidly spreading superbug.
“We have to start thinking about antibiotics as a precious limited resource,” says Brad Spellberg, an infectious disease researcher at the University of California–Los Angeles School of Medicine. “We have to both conserve and restore that resource.”
In 2009, researchers documented the first case of a microbe containing a protein called New Delhi metallo-β-lactamase-1 (NDM-1) in a Swedish person who had recently visited India’s capital. And since then, doctors have reported finding microbes expressing NDM-1, an enzyme that confers resistance to a broad range of antibiotics, in more than 100 people from India and Pakistan as well as individuals in Australia, Taiwan, Oman, Kenya, Japan, Canada and several other European countries.
Scientists had chalked up the resistance gene’s global spread to foreigners who contracted hospital-borne infections traveling to and from the Asian sub-continent. But now, in a world first, researchers have discovered NDM-1-positive bacteria outside of the clinic, suggesting that environmental exposures may play a role in the superbug’s rise, too.
In the latest report, published today — World Health Day — in The Lancet Infectious Diseases, a British team tested drinking water and other water sources in New Delhi for the presence of NDM-1-producing microbes. The researchers found more than a dozen bacterial species with this gene in two out of 50 tap water samples and 51 out of 171 puddles and small streams analyzed.
Discovering NDM-1 genes in so many species, including those responsible for cholera, dysentery and other life-threatening diseases, highlights the extreme difficulty of containing drug-resistant microbes, notes microbiologist Joakim Larsson of the University of Gothenburg in Sweden, who was not involved in the study. “These genes are so easily transmitted horizontally between species,” he says.
What’s more, the findings “give real insight into how poor sanitation and polluted drinking water is not just a problem for developing nations but actually for all inhabitants on earth,” says study co-author Mark Toleman, a microbiologist at Cardiff University School of Medicine. “The problems of sanitation and polluted water need a global response, which, if suitably addressed, will have a positive effect in every nation.”
To combat the explosion of superbugs, both the World Health Organization and the Infectious Diseases Society of America today unveiled strategic plans calling for increased surveillance of antibiotic resistant microbes, more responsible use of existing antimicrobial medicines and incentives to create new drugs.
Image: Manish Bansal, Flickr