Surfers are three times more likely to have antibiotic resistant E. coli in their guts than non-surfers, a study has revealed.
Surfers swallow 10 times more sea water than sea swimmers, and scientists wanted to find out if that made them more vulnerable to bacteria that pollute seawater, and whether those bacteria are resistant to an antibiotic.
The Beach Bums study saw a team at the University of Exeter ask 300 people, half of whom regularly surf, to take rectal swabs. They then compared the faecal samples to assess whether the surfers’ guts contained E. coli bacteria that were able to grow in the presence of cefotaxime, an antibiotic used to treat a number of bacterial infections.
Cefotaxime has previously been prescribed to kill off these bacteria, but some have acquired genes that enable them to survive this treatment.
The study, published in the journal Environment International, found that 13 of 143 (9 per cent) of surfers were colonised by these resistant bacteria, compared with four out of 130 (3 per cent) of non-surfers swabbed. That meant that the bacteria would continue to grow even if treated with cefotaxime.
Researchers also found that regular surfers were four times as likely to harbour bacteria that contain mobile genes that make bacteria resistant to the antibiotic.
They said this was significant because the genes can be passed between bacteria, potentially spreading the ability to resist antibiotic treatment between bacteria.
Last year the World Health Organisation (WHO) described antimicrobial resistance as a "global health emergency," with health experts warning that resistance to antimicrobial drugs could cause a bigger threat to mankind than cancer.
Dr Anne Leonard, of the University of Exeter Medical School, who led the research, said: "Antimicrobial resistance has been globally recognised as one of the greatest health challenges of our time, and there is now an increasing focus on how resistance can be spread through our natural environments.
“We urgently need to know more about how humans are exposed to these bacteria and how they colonise our guts. This research is the first of its kind to identify an association between surfing and gut colonisation by antibiotic resistant bacteria.”
Despite extensive operations to clean up coastal waters and beaches, bacteria which are potentially harmful to humans still enters the coastal environment through sewage and waste pollution from sources including water run-off from farm crops treated with manure.
The study authors demonstrated the prevalence of cefotaxime-resistant E. coli in bathing waters as well as the prevalence of the mobile resistance gene that make bacteria cefotaxime resistant.
The problem of antimicrobial resistance has largely focused on the prescribing of antibiotics and their use, but they said increasing priority is being placed on the role of the environment in spreading the problem in addition to transmission within hospitals, between people and via food.
Dr Will Gaze said: “We are not seeking to discourage people from spending time in the sea, an activity which has a lot of benefits in terms of exercise, well-being and connecting with nature.
“It is important that people understand the risks involved so that they can make informed decisions about their bathing and sporting habits. We now hope that our results will help policy-makers, beach managers, and water companies to make evidence-based decisions to improve water quality even further for the benefit of public health.”