An Irish research team is examining whether surfers and people who swim in rivers, lakes, or at sea, are at risk of picking up antibiotic-resistant superbugs which could cause life-threatening infections.
A team of researchers at NUI Galway are exploring whether recreational waters are carrying potentially deadly bacteria that are not routinely tested for.
While Ireland has some of the cleanest bathing waters in Europe, raw sewage is still being discharged at more than 30 locations.
The deadly superbugs are recognised as one of the greatest threats to human health.
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 — one group of 150 sea swimmers, surfers, and people who regularly use the sea, lakes or rivers for recreation, along with 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 to control the spread of antibiotic-resistant bacteria.
Professor Dearbháile 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."
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 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.
Dr Burke also warned about the dangers of heavy rainfall and its impact on beaches and sea swimming.
He said drains can overflow and carry wastewater into the sea and lakes, leading to no-swim notices being issued.
"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."