Flesh-eating bacteria, plastics in sargassum may pose ‘triple threat’ to public health

Known as Vibrio, the bacteria can cause life-threatening gastrointestinal illnesses from eating infected seafood, plus cause disease and death by infecting open wounds.

A new study found that beached Sargassum seaweed appear to contain high amounts of Vibrio bacteria, the dominant cause of death in humans from the marine environment.

Vibrio bacteria, such as Vibrio vulnificus or flesh-eating bacteria, can cause life-threatening gastrointestinal illnesses from eating infected seafood. The bacteria can also cause disease and death by infecting open wounds.

Vibrio bacteria are already known as a threat in waters around the world, but researchers sought to find a connection between the potentially deadly bacteria and two other marine phenomena: the rise of plastics and Sargassum seaweed in the ocean.

Sargassum are large microalgae blooms originating in the Sargasso Sea in the Atlantic Ocean that have accumulated on many beaches in the U.S., Mexico and other Gulf and Caribbean nations. Plastics have also accumulated in the ocean, first found in surface waters of the Sargasso Sea, according to FAU.


Combined with the increased numbers of people visiting beaches this summer, FAU said researchers on the study wondered whether plastics, Sargassum and Vibrio bacteria may pose a "triple threat to public health."

To find out, researchers studied 16 types of Vibrio collected from plastic, Sargassum, seawater and eel larvae from the Caribbean and Sargasso seas.

They discovered that Vibrio have the unique ability to "stick" to microplastics. Additionally, the microbes may also be adapting to the plastic. This can result in fish becoming infected with Vibrio after eating a piece of plastic, resulting in diarrhea that expels nutrients that stimulate the growth of nearby Sargassum.

Researchers also found that beached Sargassum appears to contain high amounts of Vibrio bacteria, increasing the chances of beachgoers coming into contact with the bacteria and possibly becoming infected.

"We really want to make the public aware of these associated risks," said Tracy Mincer, corresponding lead author and an assistant professor of biology at FAU’s Harbor Branch Oceanographic Institute and Harriet L. Wilkes Honors College.

"In particular, caution should be exercised regarding the harvest and processing of Sargassum biomass until the risks are explored more thoroughly," Mincer added.


According to FAU, co-authors of the study represent the NIOZ Royal Netherlands Institute for Sea Research, the Japan Agency for Marine-Earth Science and Technology, the Ludwig Maximilian University of Munich, Germany, Emory University, the University of Amsterdam and the Marine Biological Laboratory.