Sea swimmers could 'carry potentially deadly antibiotic-resistant bacteria' © Getty Images

Sea swimmers could ‘carry potentially deadly antibiotic-resistant bacteria’

Lakes, rivers and seas could contain antibiotic-resistant superbugs due to raw sewage, manure and effluent containing bacteria getting into the water.

Researchers are examining the risk of sea swimmers and surfers harbouring antibiotic-resistant superbugs which could cause life-threatening infections.

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A team of researchers at NUI Galway are exploring whether recreational waters are carrying potentially deadly bacteria that is not routinely tested for.

While Ireland has some of the cleanest bathing waters in Europe, raw sewage is still being discharged into the sea at more than 30 locations.

Deadly superbugs are recognised as one of the greatest threats to human health.

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The Antimicrobial Resistance and Microbial Ecology Research Group at the university is launching the PIER study (Public Health Impact of Exposure to antibiotic Resistance in recreational waters), funded by the Environmental Protection Agency (EPA).

Researchers are hoping to recruit 300 people to take part, with one group made up of 150 sea swimmers, surfers and people who regularly use the sea, lakes or rivers for recreation, and a second group of 150 people who rarely take to the water.

A key part of the project is to understand how superbugs get into human populations to help scientists learn how to control the spread of bacteria exhibiting antibiotic resistance.

Professor Dearbhaile Morris, principal investigator on the PIER project, said: “In healthy people, antibiotic-resistant bacteria behave very similarly to other common bugs, they live harmlessly on the skin, in the nose or in the bowel. This is called colonisation.

“As long as a bug stays on the skin or in the bowel, it usually does not cause a problem.

“However, once a superbug gets into a wound, into the bladder or into the blood, it can cause an infection that can be difficult to treat.

“This mostly happens in sick or vulnerable people with weaker immune systems, such as those in intensive care, the very old or the very young, and special antibiotics are then required for treatment, as ordinary antibiotics do not work.”

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Previous research carried out by the team found potentially lethal bugs in seawater around Galway.

Dr Liam Burke, co-investigator on the PIER project, said some superbugs are very common in the environment because of increased antibiotic use in humans and animals and the release of sewage, manure and effluent containing antibiotics and antibiotic-resistant superbugs, which can end up in Ireland’s lakes, rivers and seas.

“Although bathing waters are routinely tested for some bacteria, they are not tested for antibiotic-resistant bacteria, so we don’t really know to what extent they are present,” Dr Burke said.

“PIER will look into whether people who regularly use Irish waters for recreation are at risk of becoming colonised with superbugs.”

Dr Liam Burke, of NUI Galway, is co-investigator on the PIER project. He wants to find out whether people who regularly use Irish waters for recreation are at risk © Aengus McMahon
Dr Liam Burke, of NUI Galway, is co-investigator on the PIER project. He wants to find out whether people who regularly use Irish waters for recreation are at risk © Aengus McMahon

Dr Burke also warned about the dangers of heavy rainfall and its impact on beaches and sea swimming.

He said that drains can overflow and carry wastewater pollution into seawater and lakes, leading to no swim notices being issued, like those in Co Clare recently.

“If hospital waste ends up in the sea, it will more than likely contain antibiotic-resistant bacteria or a slurry stream from a farm ends up getting into the water or river, then there is potential for that to contain a high level of antibiotic-resistant bacteria,” he added.

“As the superbugs have been exposed to antibiotics, they needed to develop a mechanism to resist it. They don’t cause problems in healthy people if they stay in the gut, but if they get out of your gut by not practising good hygiene, then you could spread them around the home. A young child or elderly person could then pick it up.”

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Anyone aged 18 or over who lives on the island of Ireland can take part and those interested in supporting the research can find out more and sign up at the PIER website.

Reader Q&A: What causes antibiotic resistance?

Asked by: Eddie Friel, Hull

Antibiotic resistance is a good example of natural selection. Exposure to antibiotics increases selective pressure in bacterial populations, boosting the percentage of resistant bacteria, with new bacterial generations inheriting resistance genes.

Bacteria can sometimes pass on resistance by sharing genetic material with each other. They can also become resistant following spontaneous changes to their genes.

Some gene mutations allow bacteria to produce enzymes that inactivate antibiotics. Others change their outer structure so that antibiotics can’t gain access.

Some bacteria even develop pumping mechanisms to expel antibiotics. Overuse and misuse of antibiotics has exacerbated the problem of antibiotic resistance.

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