Giant algae may harbor flesh-eating bacteria

A massive algae bloom is drifting near a Florida beach filled with plastic and potentially harmful bacteria.

A beachgoer walks past a mass of kelp washed ashore on May 18 in Key West, Florida. Photo: Joe Raedle

According to a study published in the journal Water Research, the plastic- and bacteria-filled blobs of algae could create a “pathogen storm” in the middle of the Atlantic Ocean. Originating from the Sargasso Sea in the North Atlantic, the brown algae known as blight has become an increasingly big problem for beaches around the world in recent years, as large clumps wash ashore. NASA predicts this year’s blight bloom along the Caribbean coast and eastern Florida will be the largest on record. Experts predict the blight will hit beaches in the area in June and July.

The buildup of algae is often smelly, dense, and contains potentially dangerous bacteria from the genus Vibrio. “Vibrio can colonize both plastic and algae, and they can carry genes that can cause disease,” says Linda Amaral-Zettler, a marine biologist at the Royal Netherlands Institute for Marine Research and co-author of the study. “There have been some pretty scary cases of Vibrio infections. Their predatory behavior is rare, but it exists.”

About a dozen species of bacteria in the genus Vibrio cause vibriosis, a disease that can occur when people eat the bacteria or when they infect an open wound. When ingested, the bacteria can cause severe diarrhea, abdominal cramps, fever, and vomiting. When transmitted through a wound, one species of Vibrio sometimes causes necrotizing fasciitis.

In the study, the scientists analyzed samples of sphagnum moss from the Caribbean and Sargasso Seas and found no V. vulnificus or V. cholerae, two Vibrio species that infect humans. V. vulnificus is the only Vibrio species known to cause necrotizing fasciitis. However, the team found several previously undescribed Vibrio species that carry key genes shared with their disease-causing relatives. Their analysis suggests they also have the “mechanisms” needed to infect and cause disease in humans.

According to Amaral-Zettler, the algae contains large amounts of plastic, allowing Vibrio bacteria to quickly attach and multiply. Vibrio in algae can have many impacts on the environment. Similar to humans, fish that swallow Vibrio can suffer diarrhea, releasing nutrients into the environment, helping the algae accumulate and suck up a lot of oxygen in the water, creating a "dead zone" where other marine life cannot survive.

However, in terms of human health, the presence of Vibrio in kelp is not a concern, according to Hidetoshi Urakawa, a microbial ecologist at Florida Gulf Coast University, who was not involved in the study. Florida officials do not currently test for Vibrio in kelp washed ashore, but officials still advise beachgoers not to get too close to the algae. To guard against potential threats, including Vibrio infection, people should avoid swimming around or touching kelp whenever possible, especially if they have open wounds, according to the Florida Department of Health.

An Khang (According to Live Science )

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