Experts from University College London found traces of the DNA around London. Bacteria living around the DNA could effectively absorb their resistance. The highest levels of antibiotic-resistant genes were found in the River Thames.The scientists said better ways of filtering wastewater need to be used.
The sweltering weather may have you wanting to dive into the first pond or river you see. But, in London at least, the water may be even unhealthier than you imagined now that scientists have found traces antibiotic-resistant DNA in it.
Researchers found genes which have evolved to survive antibiotics thriving in the River Thames, Regent’s Canal and two of the city’s biggest parks.
Passing into the water from treated wastewater, the genes could be producing an ideal training ground for bacteria to mutate into untreatable illnesses.
The scientists have warned there need to be better ways of filtering antibiotic residue out of human and animal waste in order to stop the DNA spreading.
A study by University College London found antibiotic-resistant genes in the Thames, Regent’s Canal, Regent’s Park Pond and the Serpentine lake in Hyde Park.
They found most examples of the genes were present in the faeces of wild ducks, with animals probably responsible for spreading them out of rivers.
The Thames was the worst affected body of water in the city because it’s running water into which treated – and sometimes even untreated – waste is dumped.
Water filtering processes are not intense enough to remove traces of antibiotics, which are usually passed out in the excrement of the people or animals.
As a result they make their way through the treatment system and back into the rivers into which the water is discharged, the researchers suggested.
Dumped water may then be carried by animals, rain or in ground run-off into contained bodies of water like ponds and canals.
The scientists even suggested there could be antibiotic-resistant DNA in people’s drinking water – although they haven’t tested this.
Dr Lena Ciric said: ‘This shows that more research is needed into the efficiency of different water treatment methods for antibiotic removal, as none of the treatments currently used were designed to incorporate this.
‘This is particularly important in the case of water bodies into which we discharge our treated wastewater, which currently still contains antibiotics.
‘It is also important to look into the levels of antibiotics and resistant bacteria in our drinking water sources.’
Water tested by Dr Ciric’s team was found to have DNA which showed signs of resistance to the widely-used drugs penicillin, erthromycin and tetracycline.
If bacteria come into contact with DNA which are already resistant they may effectively learn the resistance from them and begin to colonise, the team said.
Antibiotic resistance has been listed as one of the top 10 threats to human health by the World Health Organization, alongside cancer, global warming and Ebola.
It happens when a bacteria evolves to become strong enough to survive antibiotic treatment, and is caused by exposure to low amounts of the drugs over long periods of time.
Some strains of the STI gonorrhoea are already showing signs of responding to first line drugs, and there are fears once easy-to-treat illnesses will become deadly.
The UCL team’s research was published by the Journal of Microbiological Methods.
28 July 2019