Mycobacterium marinum

Background

• Bacteria that causes "fish tank Granuloma"
• Can infect both immunocompetent and immunocompromised hosts

Risk Factors

• Aquarium workers and enthusiasts
• Swimming
• Handling of contaminated water

Clinical Features

Fish tank granuloma.

Fish tank granuloma spreading via lymphatic channels.

• Solitary to multiple superficial red nodules or plaques in exposed areas
  • Lesions on the hands and fingers if works with aquariums, or the knees and elbows in swimmers

Diagnosis

Diagnosis is clinical aided by histopathology. Lesions are red nodules/plaques. May progress to abscess or deep-space infections. May also disseminate (rare).

Management

1. Long-term antibiotic therapy is often needed. Antibiotic regimens include monotherapy with doxycycline, clarithromycin, bactrim, or minocycline (1, 2). However, secondary to drug high levels of drug resistance, providers may require dual drug therapy.
2. Warm compresses may also help as the bacterium is heat-sensitive.

References

• Petrini, B; "Mycobacterium Marinum: ubiquitous Agent of Waterborne Granulomatous Skin Infections." European Journal of Clinical Microbiology and Infectious Diseases. October 2006, Volume 25, Issue 10, pp 609-613
• Rallis, E; Koumantaki-Mathioudaki, E; "Treatment of Mycobacterium Marinum Cutaneous Infections." Expert Opinion on Pharmacotherapy. Volume 8, Issue 17, 2007
• Ryan, J and Bryant G. "Fish tank granuloma - a frequently misdiagnosed infection of the upper limb." J Accid Emerg Med. 1997 Nov; 14(6): 398–400.