Using coastal waters can often be quite a finicky endeavor. Working your plans around algal blooms, red tides and even the occasional sewage mishap, can often be a pretty unpleasant mess. But it turns out that swimmers and surfers may have more to fear than getting a little dirty at the beach. Aside from Giardia, a parasite that is often passed in coastal waters, it turns out that recreational swimmers at local beaches may also be at a significantly higher risk of transmitting deadly antibiotic resistant bacteria-landing them in the hospital or worse.

In the first study of its kind, published this week in the journal Environmental International and presented at the annual conference of the Society for General Microbiology, researchers with the University of Exeter Medical School investigated just how much water athletes from different water sports ingest and paired that with water sampling data to create a frightening picture revealing just how likely you are to catch a bacterium resistant to antibiotics. Looking particularly into the prevalence and spread of Escherichia coli (E. coli), the researchers were able to accurately track bacteria resistant to third-generation cephalosporins, and while they only found 0.12% of E. coli in coastal waters, the shocking amount of water consumed by surfers and sea swimmers allowed the small numbers to pose a viable threat. Divers and kayakers were found to be only at moderate risk, while sea swimmers and surfers were amongst those at the highest risk of exposure, due to their tendency to swallow more water.

"We know very little about how the natural environment can spread antibiotic resistant bacteria to humans, or how our exposure to these microbes can affect health" lead author of this study and microbiologist, Dr. William Gaze says. "People are exposed to antibiotic resistant bacteria in many ways, through person-to-person contact, via food and as a result of international travel." 

"Our research establishes recreational use of coastal waters as an additional route of exposure. With millions of people visiting beaches in England and Wales each year, there is a risk of people ingesting 3GC resistant E. coli, and it looks like water-users' exposure to all resistant bacteria could be even higher."

While the study admittedly must still continue to look at comparative rates regarding other antibiotic-resistant bacteria, the researchers say that the potential for exposure and infection make this reality a serious threat to human health. Pointing to recent initiatives in the European Union, seeking to ensure and heighten water quality standards, the researchers believe that the first step is understanding the risks. And though there is a risk, they say that enjoying local natural resources should still stay on the list of healthy activities, though perhaps not on your daily to-dos.

"Although this research has established that coastal waters are a potential source of exposure to antibiotic resistant bacteria, we're not recommending that people stop visiting the beach" coauthor of the study, Anne Leonard says. "Exercise and enjoyment of the natural environment has many established benefits for health and wellbeing, and this kind of research will help us ensure people can still make the most our coastal resources."