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Antibiotic-Resistant Bacteria Found in Sharks and Seals

Bacteria, viruses and parasites from land animals such as cats, cows and humans are sickening and killing sea mammals. Scientists have been finding a daunting number of land-based pathogens in seals, dolphins, sharks and other ocean dwellers that wash ashore dead or dying, according to an article by Christopher Solomon in the May 2013 issue of Scientific American, entitled “How Kitty is Killing the Dolphins.”

The “pollutagens” could pose a threat to people, too. Researchers are finding strains of bacteria that commonly infect people and are resistant to drugs. One harp seal had bacteria that were resistant to 13 of the 16 drugs tested by a team from Woods Hole Oceanographic Institution on Cape Cod. In recent years researchers have tested numerous sea mammals from various parts of the oceans to see which bacteria they harbor and the antibiotics those bacteria are immune to. A sample from the northwestern Atlantic is below.

The discoveries are worrisome for several reasons, Solomon writes: “A surfer or fisher with an open wound, or someone who gulps water while swimming, could get an infection that is hard to treat.” Of course people also eat seafood that could harbor the germs. Solomon also notes that sea mammals “could serve as swimming Petri dishes, nurturing and transforming diseases until they re-emerge among humans as something new and more difficult to defeat.”


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Animal

Bacteria

Number of Drugs Resisted

 

 

 

Harp seal

Chryseobacterium indologenes

13

Harbor porpoise

Sphingomonas multivorium

12

Minke whale

Vibrio alginolyticus

10

Hooded seal

Pseudomonas sp.

8

Common dolphin

Pseudomonas sp.

8

Thresher shark

Pseudomonas sp.

8

Pygmy sperm whale

Providencia rettgeri

7

Mako shark

Pseudomonas aeruginosa

6

Pygmy sperm whale

Sphingomonas paucimobili

5

Grey seal

Edwardsiella tarda

3

Striped dolphin

Staphlycoccus

2

 

Sources: Occurrence and Patterns of Antibiotic Resistance In Vertebrates off the Northeastern United States Coast. Julie M. Rose et al. in FEMS Microbiol Ecol 67, 421–431, 2009. Victims or Vectors: A Survey of Marine Vertebrate Zoonoses from Coastal Waters of the Northwest Atlantic. Andrea L. Bogomolni et al. in Diseases of Aquatic Organisms, Vol. 81: 13–38, Aug. 19, 2008.

Photo of harp seals courtesy of courosa on Flickr

 

Mark Fischetti has been a senior editor at Scientific American for 17 years and has covered sustainability issues, including climate, weather, environment, energy, food, water, biodiversity, population, and more. He assigns and edits feature articles, commentaries and news by journalists and scientists and also writes in those formats. He edits History, the magazine's department looking at science advances throughout time. He was founding managing editor of two spinoff magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 freelance article for the magazine, "Drowning New Orleans," predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. His video What Happens to Your Body after You Die?, has more than 12 million views on YouTube. Fischetti has written freelance articles for the New York Times, Sports Illustrated, Smithsonian, Technology Review, Fast Company, and many others. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti is a former managing editor of IEEE Spectrum Magazine and of Family Business Magazine. He has a physics degree and has twice served as the Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union's Robert C. Cowen Award for Sustained Achievement in Science Journalism, which celebrates a career of outstanding reporting on the Earth and space sciences. He has appeared on NBC's Meet the Press, CNN, the History Channel, NPR News and many news radio stations. Follow Fischetti on X (formerly Twitter) @markfischetti

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Scientific American Magazine Vol 308 Issue 5This article was originally published with the title “Antibiotic-Resistant Bacteria Found in Sharks and Seals” in Scientific American Magazine Vol. 308 No. 5 (), p. 0