Superbug Genes Detected in Lough Neagh
Genes capable of producing antibiotic-resistant superbugs have been identified in Lough Neagh, the UK’s largest lake, which provides drinking water to approximately 40% of Northern Ireland’s population.
Water testing revealed the presence of genes resistant to a broad spectrum of antibiotics, including carbapenems—antibiotics reserved for treating life-threatening infections when all other options have failed.
The discovery coincides with a global increase in deaths caused by antibiotic-resistant infections. In England alone, nearly 400 resistant infections are reported weekly, with an estimated 2,379 deaths linked to such infections projected for 2024, according to data from the UK Health Security Agency.
The World Health Organization (WHO) has described antimicrobial resistance (AMR) as “one of the most urgent, complex and frightening health challenges of our time.”
Samples collected by Watershed Investigations and revealed resistance genes spanning multiple antibiotic classes, including common penicillins, carbapenems, quinolones, macrolides, aminoglycosides, and cephalosporins—used to treat pneumonia and other serious infections. Genes resistant to tetracycline, commonly used in livestock, were also detected.
“Carbapenems are known as the last-line-of-defence antibiotics because they are only used when other treatments have failed,” said Will Gaze, a professor of microbiology at the University of Exeter. “If pathogens are resistant to the carbapenem antibiotics, they’re resistant to many others too.”
Resistance genes were also found in samples from a designated bathing water area on the lough. Gaze added,
“If a swimmer swallowed 30ml of the lough water, they’d get a pretty good exposure to carbapenem-resistance genes, but we don’t know what impact that has on the gut microbiome or risk of infection.”
Alongside resistance genes, markers of human, cow, and pig faeces were detected in the water. Sewage and livestock slurry provide ideal conditions for superbugs by introducing pathogens, antibiotic residues, and resistant bacteria into waterways, where they can mix, multiply, and spread.
“Sewage and livestock manures can contain pathogens that can cause serious infections,” said Gaze. “If those organisms are carrying resistance genes, they’re much harder to treat.”
Pollution and Environmental Impact
Sewage and slurry pollution are widespread issues across the UK. In Lough Neagh, such pollution has fueled extensive toxic algal blooms, visible from space, which suffocate wildlife and facilitate the spread of antibiotic resistance. Despite environmental protections, the lake’s condition has deteriorated so severely that campaigners recently held a mock funeral for it.
Northern Ireland’s Department of Agriculture, Environment and Rural Affairs (Daera) minister, Andrew Muir, reported that over 20 million tonnes of untreated sewage spill into the country’s waterways annually. Approximately 30% of Northern Ireland Water’s storm overflows release raw sewage into Lough Neagh, with 106 direct and 618 indirect discharges via rivers.
However, the problem may be larger than official figures suggest. A water industry expert noted that monitoring equipment is being installed on storm overflows but not at wastewater treatment works outfalls, where larger volumes of untreated water can enter waterways without oversight.
“Much more raw sewage is getting into rivers and lakes than the water company estimates imply,” the expert said. “Forty per cent of Northern Ireland are drinking water from a fetid pond filled with bacteria from human and animal waste, and now, unsurprisingly, there are AMR genes.”
Even treated sewage poses risks. Davey Jones, professor of environmental science and public health at Bangor University, cautioned,
“Just because wastewater’s treated, it doesn’t mean it’s safe.”
He explained that sewage overflows are harmful but intermittent and can be diluted, whereas AMR genes are continuously released through treated sewage.
“[Sewage overflows] are really bad, but they’re not always discharging and can be diluted, whereas AMR genes are pumping out every single day through treated sewage.”
Jones described sewer networks as a “mega-network of an epic breeding ground” for resistant microbes and called for improved treatment technologies at wastewater plants.
However, the Northern Ireland Fiscal Council, a non-departmental public body, stated that Northern Ireland Water lacks sufficient funding for the necessary scale of wastewater investment and must prioritize drinking water. Consequently, public funds are being used to address pollution caused by the company’s own infrastructure.
A spokesperson for Northern Ireland Water acknowledged
“decades of underinvestment,”noting the company has had
“very limited scope for upgrades”and that only a
“permanent, sustainable investment plan”will close the long-term funding gap.
They added that
“the consequences are restrictions on development, increased pollution risk and worsening pressure on the environment.”The company is introducing
“stringent targets”to reduce pollution incidents and installing new monitoring equipment to track storm overflows in the Lough Neagh catchment.
Livestock Farming and Agricultural Impact
Sewage is only part of the issue. Livestock slurry runoff from farmland contributes to algal blooms and introduces antibiotics, pathogens, and resistance genes into the lake.
Pressure from farming has increased in recent years. Since a government policy promoting intensive agriculture was introduced in 2013, pig numbers in Northern Ireland have risen from 517,075 to 744,643, while poultry numbers increased from approximately 19.5 million to 25.8 million. The country now has about 1.6 million cattle and 1.8 million sheep.
Jones described cattle as
“pathogen bioreactors on four legs,”advocating for fencing off streams to prevent animals from defecating directly into waterways and urging farmers to avoid spreading slurry at inappropriate times of the year.
“I’ve seen people doing it because their slurry tanks are full and they’ve got to get rid of the stuff,”he said.
A recent study found Escherichia coli in every sample of cattle manure tested.
Governance and Regulatory Challenges
Progress has also been hindered by governance failures. The Office for Environmental Protection watchdog found that Northern Ireland lacks an environmental regulator independent from government influence.
A source within Daera described low morale within the Northern Ireland Environment Agency, stating,
“They’re not allowed to talk, to breathe, to do their jobs. They’re not supposed to prosecute agriculture or take Northern Ireland Water to court, despite so many wastewater works being beyond capacity.”
Northern Ireland Water has largely avoided prosecution since 2007, following an agreement limiting regulators’ ability to pursue the company. However, Minister Muir withdrew that agreement on 3 March 2024.
Muir has also sought to establish an independent environmental regulator, but the proposal has been blocked at Stormont by the Democratic Unionist Party (DUP). The Daera source alleged that agriculture wields significant political influence, with many farmers forming part of the DUP’s support base.
“Antimicrobial resistance is an urgent global challenge and evidence has been found in Northern Ireland’s aquatic environments, including Lough Neagh,”said Muir, adding that plans for additional testing are underway.
“Restoring and protecting the ecological health of Lough Neagh cannot be overstated and work is under way on the Lough Neagh action plan.”
Antibiotic Use and Resistance Trends
Overuse of antibiotics in humans and livestock underpins the rise in resistance.
The UK government has set a target to reduce antibiotic use in humans by 5% by 2029 compared to a 2019 baseline. While NHS antibiotic prescriptions declined slightly between 2019 and 2024, private prescriptions more than doubled during the same period, resulting in an overall increase of 10.7% in primary care antibiotic use. Currently, 22% of all antibiotics are dispensed privately. Northern Ireland has the highest antimicrobial prescribing rate in the UK.
Ruth Chambers, senior fellow at the thinktank Green Alliance, described the situation as having
“all the ingredients to be a perfect storm for the health of Northern Ireland’s people and environment,”and called for the fast-tracking of an independent environmental protection agency.
Natalie Sims, policy adviser at the Royal Society of Chemistry, warned that the UK risks falling behind the EU, which is introducing legislation requiring countries to monitor AMR in wastewater.
“We still understand far too little about how the aquatic environment contributes to the spread of AMR,”she said.
“Without robust environmental data, we risk missing a major part of the problem.”
Global Risks and Future Outlook
The WHO warns that without urgent action, drug-resistant infections could cause 39 million deaths worldwide by 2050 and impose an annual economic burden of up to $412 billion (£307 billion).
