How Drug- & Anti-Microbial Resistance Spreads in Urban Environments

Chemical residues released from pharmaceutical and personal care products are not only becoming a major contaminant of water bodies in urban areas but are also becoming a source of drug resistance in the environment, a new study has warned.

The study, which evaluated vulnerability and resilience of urban water bodies in Guwahati city, found the presence of viruses and multidrug resistant E.coli in samples collected from the Brahmaputra river. Deepor Beel – a freshwater wetland – was found to be the least polluted in comparison to the Brahmaputra and Bharalu, the tributary-turned-urban drain.

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Researchers analysed the occurrence of pharmaceuticals and personal care products, intestine occurring virus, antibiotic resistant bacteria, metal, fecal contamination and antibiotic resistance genes, as well as the long term changes in precipitation and temperature of water. Some microbes displayed 100 percent resistance to major antibiotics – levofloxacin, ciprofloxacin, norfloxacin, kanamycin monosulphate and sulfamethoxazole.

“The Brahmaputra – due to its high diluting capacity through enormous discharge – is providing resilience to urban water, and all the pollution added by city drains is diluted in the downstream,” pointed out Dr Manish Kumar of the Indian Institute of Technology-Gandhinagar, who led the study, while speaking to India Science Wire. The research team included scientists from Sri Lanka and Japan as well.

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Water samples were collected from Brahmaputra before it entered the city as well as before its water got mixed with Bharalu. Another set of samples was collected after downstream mixing, and then from a location ten kilometres downstream from Guwahati city. The other three samples were collected upstream from the confluence point of Bharalu.

It was found that the concentration of pharmaceutical and personal care products were high in drain samples and very low in lake and river water. Researchers said it was clear that pharmaceutical and personal care product residues were directly associated with raw sewage and hence not detected in upstream or downstream samples of the Brahmaputra, or in the Deepor Beel wetland.

The study further reports contamination of drain water by toxic metals like arsenic, cobalt, and manganese, correlates with water-quality parameters such as acidity and appear to be inducing antibiotic resistance in E.coli bacteria.

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“As there are not many new antibiotics discovered all over the world, the existence of superbugs resistant to several antibiotics is alarming”, commented Ryo Honda, another member of the team from Japan. “Hundred percent resistances for all six antibiotics that we tested is the result – something we never expected,” added Tushara Chaminda, another team member from Sri Lanka.

The widespread use of antibiotics must be controlled through the attention of scientists, policymakers, and medical practitioners. “It is time to adopt a holistic approach for vulnerability and resilience evaluation of water systems, and to revise the ambient water-quality guidelines by including new-age parameters,” said Dr Kumar.

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The research team included Manish Kumar and Bhagwana Ram (IIT Gandhinagar); Ryo Honda (Kanazawa University, Japan); Chomphunut Poopipattana, Vu Duc Canh and Hiroaki Furumai (University of Tokyo);  and Tushara Chaminda (University of Ruhuna, Sri Lanka). This work was funded under India-Japan Co-operative Science Programme of the Department of Science and Technology (DST). The results of the study have been published in the journal Science of the Total Environment.

Sanghamitra Deobhanj is a contributor at India Science Wire.

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