Beaches May Be Safe Harbor for MRSA

Researchers Find Samples of the Superbug on Washington State Beaches

Medically Reviewed by Louise Chang, MD on September 14, 2009
From the WebMD Archives

Sept. 14, 2009 (San Francisco) -- Drug-resistant staph bacteria have been found on public beaches in Washington state, and beaches in other states may harbor the superbug too.

MRSA (methicillin-resistant Staphylococcus aureus) was once rarely seen outside of hospitals or other health care facilities. But in the past decade, cases have been rising in communities.

Community-acquired infections in people without risk factors such as poor hygiene are a growing concern, but little is known about environmental sources of MRSA, says Marilyn Roberts, PhD, an environmental health scientist at the University of Washington in Seattle.

The new study suggests marine water and sand may harbor the bug, she says.

Roberts tells WebMD that an individual beachgoer's risk of acquiring the infection is unknown.

"But we thought that chance of finding MRSA [at the beach] would be zero. The very fact that we found these organisms suggests that the level is much higher than we had thought," she says.

The findings were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy.

Earlier this year, other researchers reported they found MRSA in samples taken from South Florida beaches.

For the new study, Roberts and colleagues tested marine water and sand samples from beaches along the Puget Sound in Washington from February to September 2008.

Staph bacteria were found at nine of 10 beaches tested. Five of the beaches harbored strains of multidrug-resistant staph.

To the researchers' surprise, most of the samples "looked more like hospital-acquired MRSA strains than the bacteria typically found in the community," Roberts says. Three samples, from beaches 10 miles apart, were "essentially the same," she says.

Roberts says further research is needed to find out the exact source of the bacteria. In the meantime, people should continue to enjoy the beach, she says.

Her recommendations for lowering the risk of infection:

  • Make sure you get all the sand off when you get out of the water. Digging and being buried in the sand appear to raise the risk of infection.
  • Clean and bandage any open cuts or scrapes before playing in the sand.
  • If a scrape looks infected a few days after a trip to the beach, see a health care professional right away.

"It's probably prudent to shower when you come out of the water," adds Lance Peterson, MD.

"Staph is a salt-loving organism. It's not surprising to see it in the ocean," he tells WebMD. Peterson, a microbiologist at NorthShore University Health System in Evanston, Ill., was not involved with the research.

Show Sources


49th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, Sept. 12-15, 2009.

Marilyn Roberts, PhD, department of environmental and occupational health sciences, University of Washington School of Public Health and Community Medicine, Seattle.

Lance Peterson, MD, department of microbiology and infectious diseases research, NorthShore University Health System, Evanston, Ill.

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