NDM-1, a pathogenic bacteria which is resistant to most antibiotics, has been found in the public drinking water supply of India's capital, New Delhi, by scientists from Cardiff University, Wales. Among the disease-causing bacteria are those that cause dysentery and cholera. You can read about this in the medical journal The Lancet Infectious Disease.
Action is urgently required by health authorities to fight the new strains and stem their spread around the world, the scientists said. High sanitation standards need to be encouraged and maintained, the researchers stressed, and drinking water has to be safe to drink.
NDM-1 stands for New Delhi metallo-beta-lactamase-1 - it is a DNA code (a gene) some bacteria carry. When a bacteria strain has the NDM-1 gene it is resistant to virtually all available antibiotics, including the one of last resort, carbapenem, the most powerful antibiotic, used as a last remaining option for many infections, such as Klebiella and E. coli. The NDM-1 gene makes the bacterium produce an enzyme which neutralizes the activity of the antibiotic.
Put simply, a bacterium carrying the NDM-1 gene is the most powerful superbug on the planet.
The Cardiff scientists first identified the NDM-1 gene last year.
They explain that while the majority of infected individuals had recently been hospitalized, indicating that they were hospital-acquired infections, a growing number were not recently in hospital - the conclusion being that they were infected elsewhere.
The scientists took samples from the public water taps in New Delhi, as well as from waste seepage, such as street puddles.
- 4% of the public drinking water supply was contaminated with resistant bacteria
- 30% of seepage sites had resistant bacteria in them
- 11 new species of bacteria were found to be carrying the NDM-1 gene, including cholera and dysentery causing strains.
- The Shigella isolate, which carries the NDM-1 gene, is resistant to all appropriate antibiotics - it can carry dysentery
"These are extremely worrying results. We found resistant bacteria in public water used for drinking, washing and food preparation and also in pools and rivulets in heavily-populated areas where children play. The spread of resistance to cholera and to a potentially-untreatable strain of dysentery is also a cause for extreme concern."
650 people in India have no access to proper flush toilets; there are even more people with no clean water, according to a United Nations report. The sewage system in New Delhi is said to be bursting at the seams. The authors say that local temperatures and monsoon flooding make the capital an ideal place for NDM-1 to spread.
"This is an urgent matter of public health. We need similar environmental studies in cities throughout India, Pakistan and Bangaldesh to establish how widespread resistant bacteria are. If we are to maintain our ability to treat severe infection in vulnerable patients, this action is vital.
The environmental spread of bacteria is also an international issue. We have discovered patients in the UK and Europe carrying NDM-1 who did not visit hospitals while in India. Our research team at Cardiff would be happy to advise the World Health Organisation and the Asian health authorities on the action that needs to be taken."
"Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study"
Prof Timothy R Walsh PhD, Janis Weeks BSc, David M Livermore PhD, Mark A Toleman PhD
The Lancet Infectious Diseases, Early Online Publication, 7 April 2011
Written by Christian Nordqvist