Research shows “there are now reservoirs of highly resistant gut bacteria in the environment”
July 27th 2014
A team of scientists from Birmingham University, Warwick University, and the Health Protection Agency have been doing research into the presence of bacteria in water bodies near waste water treatment plants. The scientists analysed sediment samples from the upstream and the downstream of a sewage works and found the presence of bacteria that are resistant to a class of antibiotics widely used to treat a range of health problems, including meningitis and septicaemia. The disturbing aspect of the findings is that there were increased numbers of clinically-important antibiotic-resistant bacteria downstream of a large sewage plant compared to upstream. The scientists also discovered the presence of E. coli bacteria, the first time this has been discovered in the wild, and this was seven times more common downstream than upstream.
The scientists have concluded that waste water treatment plants “could be unwittingly helping to spread antibiotic resistance.” The research, published in the Journal of Antimicrobial Chemotherapy , suggests that the processing of human, farm and industrial waste all together in one place might be making it easier for bacteria to become resistant to a wide range of even the most clinically-effective antibiotics. Professor Elizabeth Wellington of the University of Warwick, who led the study, said: “The way sewage plants mix up different types of waste means they’re hotspots, helping bacteria share genes that mean they can deactivate or disarm antibiotics that would normally kill them. It seems that with so many different types of bacteria coming together in sewage plants we could be giving them a perfect opportunity to swap genes that confer resistance, helping them live. This means antibiotic-resistant bacteria may be evolving much faster than they would in isolation.”
Earlier studies of bacteria in the environment have investigated farming practices and waste processing methods and concluded that these were contributing to reservoirs of resistant bacteria in the environment. However, few studies had investigated whether waste water effluent contributes to the problem.
Professor Wellington said: “A greater volume of antibiotics is used in farming than in anything else. Huge amounts are used globally, mainly for treating infections in food animals but also to promote growth.” Her research suggests that resistance is spreading because of a specific bacterial gene, which is the most common antibiotic-resistant gene to cause failures in the treatment of infections. “It’s the first time anyone has seen this gene in UK rivers,” said Wellington. “The problem is we’re using river water to irrigate crops, people swim or canoe in rivers, and both wildlife and food animals come into contact with river water. These bacteria also spread during flooding. And with more flooding and heavy rain, this could get worse.”
“We’re on the brink of Armageddon and this is just contributing to it,” she said. “Antibiotics could just stop working and we could all be colonised by antibiotic-resistant bacteria.”
For further information, see the article on the “Planet Earth” website at “Sewage treatment contributes to antibiotic resistance”.
 G. C. A. Amos, P. M. Hawkey, W. H. Gaze and E. M. Wellington, Waste water effluent contributes to the dissemination of CTX-M-15 in the natural environment, Journal of Antimicrobial Chemotherapy 2014; 69: 1785 – 1791, published online 5th May 2014, doi:10.1093/jac/dku079.