Fears hospital superbugs will end up in food as study finds elevated levels

Hospitals flushing out water laced with superbugs are potentially contaminating the food chain, experts warn.

New analysis of drains near four Scottish NHS sites found more than 10 times the amount of antibiotic-resistant germs compared with domestic sewers.

The power of drugs to defeat infections is being eroded as bacteria evolve to become immune to medication.

And there are fears that even minor operations could soon become hazardous procedures.

Now the latest study – led by Edinburgh University’s Usher Institute – claims hospitals are generating a soup of superbugs that are then washed into other wastewater streams.

It all gathers at treatment plants, increasing the risk of resistant bacteria mixing and multiplying further.

Then the residue is either expelled into our rivers or used as farm fertiliser to grow food for human consumption.

Last night, Charles Watson, chairman of the campaign group River Action, said: “The reality is our environmental regulators are hopelessly unprepared for dealing with the severe threats posed by such pollutants.

“There is no systematic monitoring of antibiotic-resistant bacteria.

“Water companies and health boards should be doing everything in their power to remove such bodies from discharged water.

“However, nothing will effectively happen without unequivocal direction from government to rigorously monitor for such pollutants and enforce the strongest regulations to prevent them ever entering our watercourses.”

Superbugs

The latest study is a first attempt to gauge the amount of superbugs in Scottish wastewater and how much of them come from hospitals.

Academics analysed untreated effluent samples from eight sites. Four were hospitals: the Victoria in Kirkcaldy, St John’s in Livingston, Hairmyres in Hamilton, and the Borders General in Melrose.

And four were residential areas in Stirling, East Kilbride, Grangemouth and Hawick. Samples were also taken from wastewater treatment plants (WWTPs) near each of the eight.

In total, 15,115 different types of bacteria were detected and, among them, 360 gene groups known to confer resistance against antibiotics. Compared with community samples, water from hospitals contained 10% more bugs but 12 times the amount of resistant genes.

These genes are able to transfer between different types of bacteria, giving them the ability to survive a course of antibiotics. It means infections from, among others, E.coli, Strep A and MRSA become less treatable and therefore more deadly.

The hospital pollutants became diluted as they moved downstream – but their signal was still detected in water gathering at WWTPs, which are a suspected melting pot for gene transfer. A collaboration between Edinburgh University, Scottish Water and the Technical University of Denmark, and published in the journal Science Of The Total Environment, the study states: “Infections caused by antibiotic-resistant bacteria are a leading cause of mortality globally and are growing in number. We conclude that hospital and community wastewater resistomes differ. Resistance genes were more enriched and diverse in hospital wastewater compared to community and WWTPs.”

The authors recommended a new surveillance regime of hospital effluent so that spikes can be spotted early.

In particular, they found excesses of blaOXA-233 at Hairmyres and Borders General and also at their neighbouring WWTPs. This gene is known to knock out antibiotics that treat Pseudomonas, a bacterium that preys on weakened hospital patients and was also one of the most common identified in the study.

It states: “Regular testing could show whether the elevated levels are persistent and point to a need for further investigations to identify the source.”

Dr Joanna Cloy, senior projects manager of environmental charity Fidra, said: “There are many unknowns, but the spread of these bacteria and genes in the environment – and potential contamination of the food chain – could result in the development of antibiotic resistance, which itself is a threat to modern medicine.

“Genetic material is not regularly monitored in effluent, treated sewage sludge or the waters and soils that receive them. So regulators are unable to determine the levels at which harm is caused.”

Sewage

It recently emerged sewage sludge destined for farms also contained cancer-causing chemicals.

Tests at Scottish WWTPs found traces of toxins including TCDD, which was the most lethal component of Agent Orange, the infamous Vietnam War herbicide brew that left a legacy of tumours and birth defects.

A Scottish Water spokesman said: “The research findings, which are good news, outline that monitoring can be successfully used to help understand antimicrobial resistance in communities.

“The types and quantities of resistance in this study were in line with expectations. The use of antibiotics by people is the main source of antibiotic-resistant bacteria in wastewater.

“Scottish Water has no formal or regulatory obligations to conduct surveillance of hospital effluents. However, we are contributing to research to enable greater understanding of resistance genes within the wastewater setting. These projects will help determine future options.”

John Redshaw, principal scientist at the Scottish Environment Protection Agency (SEPA), said: “Pharmaceutical pollution of waters is a global challenge. SEPA will continue to work with UK and global partners to identify and prioritise the medicines that are presenting the greatest risks to our water environments and explore ways in which such information might be used to inform future regulatory standards.”

The Scottish Government said the NHS is implementing a “range of measures to reduce and eliminate pharmaceutical pollution from wastewater systems”.

Rising risk of resilient bugs

Superbugs are strains of bacteria that are resistant to one or more types of antibiotic and other types of medication used to treat the infections they cause.

Some superbugs can cause pneumonia, skin or urinary infections or even sepsis.

There have been a number of serious superbug outbreaks that have affected the NHS in the UK down the years – including the C.difficile and MRSA.

The MRSA bug is harmless on the skin but needs immediate treatment if it gets inside the body. The World Health Organization says superbugs will be the leading cause of deaths by 2050.