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Mycobacterium Marinum

Mycobacterium marinum is a bacterium most commonly found in fresh or salt water that may cause infections in fish and people. It is a natural part of the ecosystem of the Chesapeake Bay and its tributaries and also in other water bodies around the world. In humans it can cause skin and joint infections.

The majority of reported Maryland human cases of Mycobacterium marinum occur in Anne Arundel County, which has a longer coastline than any other Maryland county and thus more people with water contact at work or play.

To reduce risk of infections with Mycobacterium marinum:

  • Avoid fresh or salt water activities if there are open cuts, scrapes or sores on your skin.
  • Persons with weakened immune systems can reduce risk of infection by carefully covering cuts, scrapes or sores during fresh or salt water activities and while cleaning fish tanks or handling, cleaning or processing fish.
  • Wear heavy gloves (leather or heavy cotton) while cleaning or processing fish, especially fish with sharp spines that may cause cuts, scratches, or sores to the hands and skin. Wash hands thoroughly with soap and water after fish processing, or use a waterless cleanser.
  • Wear waterproof gloves when cleaning home aquariums or fish tanks. Wash hands and forearms thoroughly with soap and running water after cleaning the tank, even if gloves were worn.
  • Ensure regular and adequate chlorination of swimming pools to kill any bacteria that may be present.

For more information about Mycobacterium marinum, see the Mycobacterium Marinum Fact Sheet from the Maryland Department of Health and Mental Hygiene.