Antibiotic-resistant bacteria are becoming an increasing threat to recreational water users, and new research from the University of Exeter in the UK shows surfers are at the highest risk of all.

The Beach Bums Project

In one of our first Beach Basics articles we presented a brief history of surfers and water quality, highlighting how “if the ocean is going to make anyone sick, surfers are first in line.” Written in 2015, that article mentioned the start of an exciting new research project lead by Dr. Anne Leonard of the University of Exeter Medical School in the UK, known as the ‘Beach Bum Survey’.

Over the past two years Dr. Leonard and her team have collected fecal samples from 273 recreational water users at beaches in the UK. Half of the samples came from surfers. The Beach Bum findings were published on January 14, 2018 in the journal Environment International. Most noteworthy, surfers are three times more likely than other recreational water users to be “colonized” by antibiotic-resistant bacteria such as E.coli, the study found.

“This research is the first of its kind to identify an association between surfing and gut colonisation by antibiotic resistant bacteria,” Dr. Leonard said.

The researchers attribute the increased presence of antibiotic resistant E.coli in surfers to the fact that surfers swallow up to ten times more water than other recreational water users. The presence of E.coli is not a new phenomenon in recreational water and its users. However, antibiotic resistant strains of the E.coli bacteria are on the rise in recreational waters and pose a increasing threat to our health; both in and out of the water.

Infographic from the WHO

What are antibiotic-resistant bacteria?

The Centre for Disease Control and Prevention (CDC) defines antibiotic resistance as:

“the ability of bacteria to resist the effects of an antibiotic. Antibiotic resistance occurs when bacteria change in a way that reduces the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply, causing more harm.”

As bacteria develop this process occurs naturally . However, the extensive use of antibiotics in humans and animals are accelerating the process, increasing the rate and scale that antibiotic-resistant bacteria (ARB) develop.

Modern medicine relies heavily upon antibiotics. Therefore, antibiotic resistance leads to increased medical costs, longer stays in the hospital, and ultimately increased morbidity and mortality from infection. Recreational water users are at risk as the presence of ARB increases in our waterways. As the study shows, exposure to ARB during recreational water activities can lead to gut colonization.

ARB and Recreational Water Activities

While Dr. Leonard’s research demonstrates a link between recreational water users and colonization by ARB, the question remains: how are ARBs getting into our waterways in the first place?

In a previous article we detailed the different types of sewer systems, including combined sewer systems. Combined sewer systems mix and transport both waste and stormwater together to treatment facilities. However, if the volume of waste and stormwater exceeds the capacity of the holding tanks, a Combined Sewer Overflow (CSO) occurs, resulting in sewage being discharged into nearby water bodies. These events are not uncommon. Every year over 200 billion litres of raw partially treated sewage enter Canadian waterways, while 4.5 trillion litres (1.2 trillion gallons) of untreated sewage, storm water and industrial waste are discharged into US waterways annually.

Sewage makes its way into our waterways in big and small ways. In 2013, a rainstorm in Toronto resulted in over 1 billion litres (265 million gallons), and in January of 2018 a CSO occurred in Monterey, California where almost 190 million litres (5 million gallons) of sewage were dumped into the ocean.

Dr. Tong Zhang of the University of Hong Kong as shown that increasing amounts of antibiotics are entering our wastewater systems through urine, feces, and hospital waste. This allows antibiotics to mingle in sewage holding tanks with bacteria like E.coli. As they mingle, bacteria develop resistance to the antibiotics, creating ARB. When a CSO occurs, these ARB are then discharged into recreational waters, posing a threat to those who recreate in them.

Photo by Harald Groven

Sewage contamination poses a great risk to public health- and that risk comes with a heavy price tag.

A 2018 report published by researchers from the University of Illinois in Chicago found that approximately 90 million recreational water illnesses occur each year in the US, bringing with them anywhere between $2.2 and $3.7 billion in associated medical costs. This was the first study of its kind, weighing the annual, national burden that recreational water illnesses place on the medical system; a burden that will continue to be exacerbated with the continued contamination of beaches, rivers, lakes, and swimming holes from sewage and stormwater. While this issue is multifaceted, addressing sewage contamination is paramount to curbing the public health risks associated with polluted recreational waters.

Further Resources

To read more about the Beach Bums Survey, check out the original article here.

To learn more about the costs of recreational illness in the US, read our full report here.

Surfers against Sewage (SAS) is an amazing organization who worked with Dr. Leonard on this project. Learn more about their work here.

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