Your Aquarium May Harbor Bacterial Organism Mycobacterium Marinum
October 7, 2013

Bacterial Skin Infection Caused By Aquariums Often Under-Diagnosed

redOrbit Staff & Wire Reports - Your Universe Online

Mycobacterium marinum infection, a skin condition associated with exposure to contaminated water in home aquariums, is under-diagnosed, according to new research presented Saturday at the Infectious Diseases Society of America's annual meeting in San Francisco (IDWeek 2013).

The study, which was sponsored by the Henry Ford Hospital in Detroit, Michigan, reported that the infection is difficult to diagnose and treat because skin lesions typically do not appear for two to four weeks after incubation.

As a result, treatment becomes delayed and antifungal and/or antibacterial agents are used unnecessarily and with little effect, the authors explained. Furthermore, during the incubation period, patients often fail to recall the source of the exposure, which is often traced back to them cleaning their aquariums.

Lead author Dr. George Alangaden, an infectious disease physician at the Henry Ford Hospital, and his colleagues said that the infection typically results when bacteria in non-chlorinated water in the aquarium attacks an open sore on the individual’s hand or arm.

“People just don't know or think about their fish tank harboring this bacterial organism,” said Alangaden. “And unless they're directly questioned about it by their physician, who may or may not have adequate knowledge of Mycobacterium marinum and its prolonged incubation period, appropriate treatment often gets delayed.”

The investigators conducted a retrospective study from January 2003 through March 2013. They identified five patients between the ages of 43 and 72 who had been treated at the Henry Ford Hospital for Mycobacterium marinum, which resembled reddish skin lesions or bumps on the hands or arms.

“Skin biopsies performed on all five patients confirmed the infection,” the health care center said. “The incubation period before skin lesions appeared ranged from 11 to 56 days. While all five patients responded effectively to antibiotic treatment, it took on average 161 days from the time of initial presentation to time of treatment.”

Mycobacterium marinum is not a life-threatening illness, but it remains an unrecognized cause of skin infection,” added Dr. Alangaden. “To accelerate diagnosis and treatment, physicians are encouraged to ask detailed questions about the patient's history, especially questions about potential exposure to aquariums.”

Mycobacterium marinum results in an unusual clinical condition termed swimming pool granuloma or fish tank granuloma. The ailment is typically seen in individuals who have had exposure to some type of marine environment, such as fish tanks, and presents itself as granulomatous lesions, usually on portions of the extremities prone to abrasions (such as the hands). The lesions usually begin as papules that then ulcerate and scar, and while the disease is often localized, some patients can develop a nodular lymphangiitis similar to sporotrichosis.