Feb. 17, 2014 -- New research has indicated a rise in superbugs at tourist sites along the Upper Ganges River, in the foothills of the Himalayas, caused by annual visits. In particular, the spread of antibiotic resistance to one of the most pristine locations in Asia is linked to human pilgrimages.
Experts from Newcastle University, UK, and the Indian Institute of Technology in Delhi (IIT-Delhi), sampled water and sediments at seven sites along the river. They found that in May and June, when hundreds of thousands of visitors travel to Rishikesh and Haridwar to visit sacred sites, levels of resistance genes that lead to superbugs were found to be around 60 times greater than other times of the year.
Publishing their findings in the journal Environmental Science and Technology, the team says it is important to protect people visiting and living at these sites. Likewise, they argue that preventing the spread of resistance genes that promote life-threating bacteria could be achieved by improving waste management at key tourist sites.
"This isn't a local problem -- it's a global one," said Professor David Graham, an environmental engineer based at Newcastle University. "Temporary visitors from outside the region overload local waste-handling systems, which seasonally reduces water quality at the normally pristine sites."
Graham continued, "The specific resistance gene we studied, called blaNDM-1, causes extreme multi-resistance in many bacteria, therefore we must understand how this gene spreads in the environment. If we can stem the spread of such antibiotic resistant genes locally -- possibly through improved sanitation and waste treatment -- we have a better chance of limiting their spread on larger scales, creating global solutions by solving local problems."
Funded by the Engineering and Physical Sciences Research Council (EPSRC), the aim of the research was to understand how antibiotic resistance was transmitted due to a specific human activity. Local "hot-spots" of antibiotic resistance exist around the world, particularly densely-populated regions with inconsistent sanitation and poor water quality.
By comparing water quality of the Upper Ganges in February and again in June, the team showed that levels of blaNDM-1 were 20 times higher per capita during the visiting season than at other times. Further, monitoring levels of other contaminants in the water, the team showed that overloading of waste treatment facilities was likely to blame and that in many cases, untreated sewage was flowing straight into the river where the pilgrims bathe.
Worldwide, concern is growing over the threat from bacteria that are resistant to the so-called "last resort" class of antibiotics known as Carbapenems, especially if resistance is acquired by aggressive pathogens. Of particular concern is NDM-1, which is a protein that confers resistance in a range of bacteria. NDM-1 was first identified in New Delhi and coded by the resistant gene blaNDM-1.
Until recently, strains that carry blaNDM-1 were only found in clinical settings, but in 2008, blaNDM-1 positive strains were found in surface waters in Delhi. Since then, blaNDM-1 has been found elsewhere in the world, including new variants. There are currently few antibiotics to combat bacteria that are resistant to Carbapenems, and worldwide spread of blaNDM-1 is a growing concern.
Graham, who is based in the School of Civil Engineering and Geosciences at Newcastle University, UK, said the team had planned to repeat their experiments last year, but the region was hit by massive floods in June and the experiments were abandoned.
The team has since returned to Rishikesh and Haridwar and hope their work will prompt public action to improve local sanitation, protecting these socially important sites. On a global scale, they want policymakers to recognize the importance of clean drinking water in the fight against antibiotic resistance.