Antibiotic resistance must be tackled in the field

Child playing on muddy shore

22 November 2016 by Sylvie Kruiniger

'Antibiotics: Handle with Care.' That was the theme of this year's World Antibiotic Awareness Week. 'Don't take them if you can get well without them. Don't prescribe them if you're not certain they'll help. And don't bypass medical advice to get them.'

But what about when you do take antibiotics and they pass through you, into the sewers and out into rivers? What about when we feed them to animals and then spread their manure over fields? Does doing that then put pressure on naturally-occurring bacteria in the environment to develop resistance to antibiotics?

It's not only the antibiotics that could be encouraging resistance. We release lots of other things into our water that can kill bacteria and drive them to develop resistance to protect themselves. Things like tiny particles of metal and elements of cleaning products. In fact, there are far more of these in our waterways than there are antibiotics. But we don't yet know how much these different elements and their different concentrations drive antibiotic resistance.

There's another factor too: as well as antibiotics in our wee, there's also drug-resistant bacteria in our poo. Our sewage gets treated, but a lot of resistant bacteria still ends up in our rivers. Dung from animals, which also contains drug-resistant bacteria, is spread onto land and also runs into rivers.

Those drug-resistant bacteria can share the genes that protect them with other bacteria. That gene-transfer process seems to be hugely important in increasing resistance to any drugs or cleaning products we have.

In 2014, we reported on work led by Professor Elizabeth Wellington that showed some drug-resistant bacteria are much more common downstream from a sewage works than upstream. Dr Andrew Singer is working with Professor Wellington and Dr William Gaze on a joint project funded through NERC to find out what causes increased levels of resistant bacteria in rivers. Is it the metals, the cleaners, the antibiotics or is it the gene copying process?

"At the moment it looks like all these factors could be driving resistance," explains Dr Gaze, but they would all have different solutions. We want to know if we should be focusing on any of them over the others."

Dr Singer's group is leading experiments in rivers using systems called flumes. The flumes make a 'river within the river', giving them a controlled area they can test but that is still as close to the natural environment as possible. In different channels of the flume they can change variables such as how much sewage enters the system or what antibiotics flow through.

Dr Singer says, "We just don't have the wide body of research to fully inform how policy should tackle antimicrobial resistance in the environment. We can't yet prove that more antibiotic resistance in the environment will mean more drug-resistant infections. However, I think we are at the point where it looks likely that resistant bacteria in the environment are a part of the problem; we must start working with all stakeholders if we are to slow or reverse current trends."

"I don't think we can overstate the importance of dealing with antimicrobial resistance," says Professor Wellington. "Researchers are tackling it on multiple fronts: treatment, prevention and clean up. But we've got a finite period of time to act before a disastrous outbreak happens."

Earlier this year, the Review on Antimicrobial Resistance led by Jim O'Neill warned that, if left unchecked, antimicrobial resistance could cause 10 million deaths a year around the globe by 2050 - external link. We funded Dr Singer's project under the call 'Antimicrobial resistance in the real world' which NERC is leading as part of the antimicrobial resistance cross-council initiative - external link. Projects funded through the scheme are working to make sure we understand antimicrobial resistance completely so we can tackle it effectively. Find out more about the Antimicrobial Resistance in the Real World programme.

'Review of Antimicrobial Resistance in the Environment and Its Relevance to Environmental Regulators' - AC Singer, H Shaw, V Rhodes, A Hart, Frontiers in Microbiology, 1 Nov 2016. DOI: 10.3389/fmicb.2016.01728 .

Hear more from Andrew Singer in his blog Antimicrobial Resistance in the Environment - external link.

We recently announced further funding for research into antimicrobial resistance in partnership with the other six research councils and India.