‘Drinking from a fetid pond’: superbug-creating genes found in UK’s largest lake | Water

Genes that can create antibiotic-resistant superbugs have been detected in Britain’s largest lake, which provides drinking water to around 40% of Northern Ireland.

Testing of water from Lough Neagh, which has a surface area 26 times greater than Windermere, found genes resistant to a wide range of antibiotics, including carbapenems, used for life-threatening infections when all other treatments have failed.

The discovery comes as deaths from antibiotic-resistant infections increase worldwide. Around 400 resistant infections are reported every week in England, with deaths linked to them reaching an estimated 2,379 in 2024, according to UK Health Security Agency data.

The World Health Organization (WHO) describes this antimicrobial resistance (AMR) as “one of the most urgent, complex and frightening health challenges of our time.”

Resistance genes were found in samples obtained by Watershed Investigations and the Guardian, spanning several classes of antibiotics, from common penicillins to last-resort carbapenems, as well as quinolones, macrolides, aminoglycosides and cephalosporins used to treat pneumonia and other serious infections. There were also genes resistant to tetracycline, which is widely used in livestock.

“Carbapenems are known as last-line antibiotics because they are used only when other treatments have failed,” said Will Gaze, professor of microbiology at the University of Exeter. “If pathogens are resistant to carbapenem antibiotics, they are also resistant to many other antibiotics.”

Samples taken from a designated bathing water area on the pond were also affected. Gaze said: “If a swimmer swallows 30ml of water, they are pretty well exposed to carbapenem resistance genes, but we don’t know what effect this has on the gut microbiome or risk of infection.”

In addition to resistance genes, traces of human, cow and pig feces were also detected in the water. Sewage and livestock sludge create ideal conditions for superbugs, pathogens, antibiotic residues and resistant bacteria to flow into waterways where they can mix, multiply and spread.

“Sewage and animal manure may contain pathogens that can cause serious infections,” Gaze said. “If these organisms carry resistance genes, they are much more difficult to treat.”

Sewage and sludge pollution is common throughout the UK. It has fueled massive toxic algal blooms in Lough Neagh that are visible from space, choking wildlife and helping to spread antibiotic resistance. Despite various environmental protection measures, the lake’s health is so poor that campaigners recently staged a mock funeral for it.

Northern Ireland Department of Agriculture, Environment and Rural Affairs (Daera) minister Andrew Muir said more than 20 million tonnes of untreated sewage was dumped into the country’s waterways each year. Approximately 30% of Northern Ireland Water’s storm floods dump raw sewage into Lough Neagh via rivers, 106 directly and 618 indirectly.

However, the size of the problem may be even greater. A water industry expert said the monitors are installed at the water company’s storm floodplains, but not at the outlets of wastewater treatment plants, where larger volumes could enter waterways uncontrolled.

“Much more raw sewage is flowing into rivers and lakes than the water company’s forecasts imply,” the expert said. “40 per cent of Northern Ireland drinks from a stinking pond full of bacteria from human and animal waste and now, unsurprisingly, has AMR genes.”

But even treated sewage poses risks. Davey Jones, professor of environmental science and public health at Bangor University, warned: “Just because wastewater is treated does not mean it is safe.”

“[Sewage overflows] “It’s really bad, but they don’t always discharge and can be diluted, whereas AMR genes are pumped out every day through treated sewage.”

He described sewer networks as a “mega-network of epic breeding ground” for resistant microbes and called for better treatment technologies at wastewater plants.

But the Northern Ireland Fiscal Council, a non-departmental public body, said the company did not have sufficient funding for the scale of wastewater investment required and was forced to prioritize drinking water instead. As a result, Northern Ireland Water is spending public money cleaning up pollution from its own infrastructure.

A Northern Ireland Water spokesman acknowledged “decades of underinvestment”, saying the company had “very limited scope for upgrades” and only a “permanent, sustainable investment plan” could bridge the long-term funding gap.

Meanwhile, they said, “the consequences are restrictions on development, increased pollution risk and worsening pressure on the environment.” Officials added that “stringent targets” to reduce pollution incidents had been introduced and new monitoring equipment had been installed to monitor storm overflows in the Lough Neagh catchment.

But sewers are only half the story. Livestock slurry runs off farmland, fueling algal blooms and flushing antibiotics, pathogens and resistance genes into the lake.

Pressure from agriculture has intensified in recent years. Since a government policy encouraging intensive farming came into force in 2013, pig numbers in Northern Ireland have increased from 517,075 to 744,643, while poultry numbers have also increased from around 19.5 million to 25.8 million. Currently, there are approximately 1.6 million cattle and 1.8 million sheep in the country.

Describing cattle as “four-legged pathogen bioreactors”, Jones argued that streams should be fenced to prevent animals from defecating directly into waterways and that farmers should stop spreading slurry at the wrong time of year. “I’ve seen people do this because their sludge tanks are full and they need to get rid of the stuff,” he said.

A recent study found to parcel in every sample of cattle manure tested.

Progress has also been hampered by governance failures. Northern Ireland lacks an environmental regulator independent of government influence, an Environmental Protection Office watchdog has found.

A Daera source said morale at the Northern Ireland Environment Agency had collapsed. “They’re not allowed to talk, they’re not allowed to breathe, they’re not allowed to do their job. They’re not supposed to be suing agriculture or taking Northern Ireland Water to court, despite many wastewater works being over capacity.”

Northern Ireland Water has largely avoided investigation since 2007, when a deal was signed limiting regulators’ ability to pursue the company, but Muir withdrew that deal on March 3 this year.

Muir also tried to set up an independent environmental regulator but the proposal was blocked by the Democratic Unionist Party (DUP) at Stormont. The Daera source claimed agriculture has significant political influence and many farmers form part of the DUP’s support base.

“Antimicrobial resistance is a pressing global issue and evidence has been found in Northern Ireland’s aquatic environments, including Lough Neagh,” Muir said, adding that there were plans for further testing. “Restoring and protecting the ecological health of Lough Neagh cannot be overstated and work continues on the Lough Neagh action plan.”

The overuse of antibiotics in both humans and animals underlies the increase in resistance.

To combat this problem, the UK government has a target of reducing the use of these substances in humans by 5% by 2029, compared to a 2019 baseline. NHS antibiotic prescriptions fell slightly between 2019 and 2024, but private prescriptions more than doubled over the same period and overall primary care use increased by 10.7%; 22% of all antibiotics are now distributed privately. Northern Ireland has the highest rate of antimicrobial prescribing in the UK.

Ruth Chambers, a senior fellow at think tank Green Alliance, said the situation “has all the makings of a perfect storm for the health of the people and environment of Northern Ireland” and called for swift action by an independent environmental protection agency.

Natalie Sims, a policy adviser at the Royal Society of Chemistry, warned that the UK risks falling behind the EU, which has introduced laws requiring countries to monitor AMR in wastewater. “We still understand very little about how the aquatic environment contributes to the spread of AMR,” he said. “Without solid environmental data, we risk missing a big part of the problem.”

The WHO warns that unless urgent action is taken, drug-resistant infections could kill 39 million people worldwide by 2050 and impose an annual economic burden of up to $412 billion (£307 billion).