Swedish scientists have used DNA sequencing to show that bacteria down-river from polluting antibiotics factories in India are full of resistance genes, protecting them from otherwise effective antibiotics.
Many of the substances in our most common medicines are manufactured in India, and some of these factories release huge quantities of drugs to the environment, the Swedish scientists said. They used a novel method based on large-scale DNA sequencing to show that bacteria in polluted rivers become resistant to a range of antibiotics.
“Since we buy medicines from India, we share moral responsibility to reduce the pollution,” said Joakim Larsson, associate professor at the Sahlgrenska Academy, University of Gothenburg, one of the scientists behind the study.
“If the pollution contributes to resistance development in clinically important bacteria, it becomes our problem also in a very direct way,” he added.
“We have combined large-scale DNA sequencing with novel ways to analyse data to be able to search for thousands of different antibiotic resistance genes in parallel,” said Erik Kristiansson, assistant professor at Chalmers University of Technology. “Such an approach may become useful also in hospitals in the future.”
Other scientists said they fear that this pollution may contribute to the development of untreatable infectious diseases world-wide. Several international experts, interviewed by the journal Nature, described the results as worrying.
“Even if the bacteria found are not dangerous to humans or other animals in the area, they may transfer their resistance genes to bacteria that are,” said Dave Ussery, a microbiologist at the Technical University of Denmark.
David Graham at Newcastle University, UK, described the Indian site: “In a way, it's sort of like a beaker experiment that tests the worst-case scenario, only this is in a natural system.”
Björn Olsen, an infectious-disease specialist at Uppsala University in Sweden compared the resistance with volcano-ash. “The cloud is going to drop down somewhere else, not just around the sewage plant,” he said.
The study was carried out at the Sahlgrenska Academy, University of Gothenburg in collaboration with Chalmers University of Technology and Umeå University, Sweden, and was published by the online journal PLoS ONE.