1630. Mycobacterium marinum remains an unrecognized cause of insidious skin infection  
Session: Poster Abstract Session: Mycobacterial Infections
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C

Mycobacterium marinum is an environmental pathogen found in non-chlorinated water that rarely causes disease. Typically, M. marinum causes cutaneous infection within 2 to 4 weeks of direct inoculation secondary to trauma from fish fins and bites, or from exposure to contaminated water in aquariums. Due to the prolonged incubation period patients (pts) may not recall the exposure, and diagnosis and treatment is often delayed. Prompted by 2 recent cases, we sought to determine the occurrence of M. marinuminfections in our institution during the last decade.


The study was conducted at Henry Ford Hospital a 900-bed tertiary care center. Pts with positive tissue culture for M. marinumbetween 1/2003 and 3/2013 were identified using the laboratory database. Medical records of pts were retrospectively reviewed. Relevant demographic, epidemiologic and clinical data were examined. 


Five pts ages 43 to 72 years had bacteriologically confirmed M. marinum skin infections. Two pts were diabetic, while 3 pts had no medical conditions. In all pts infection was preceded by trauma to the hand. Erythema and swelling at site of the injury evolved into inflammatory nodules with linear progression towards the arm and axilla, despite treatment with anti-streptococcal/staphylococcal antibiotics. In addition, 2 pts also received antifungal therapy due to suspicion of sporotrichosis. Skin biopsies were subsequently performed in all pts and specimens showed granulomatous inflammation with acid fast bacilli, and cultures yielded M. marinum.Incubation periods ranged from 11 to 56 days (d). Mean time from initial presentation to antimycobacterial treatment was 161 d (range: 33 to 379 d). All pts showed slow response to specific treatment.


Diagnosis and management of M. marinum infection is difficult. Physicians should be aware of the prolonged incubation periods. Patients presenting with insidious nodular skin infections affecting the upper extremities should be asked about aquatic exposure. Tissue biopsies for microbiological studies are essential to establish an early diagnosis and prompt initiation of appropriate therapy.

Marisa Miceli, MD1, Molara Alexis, MD1, Linoj Samuel, PhD2, Mayur Ramesh, MD1 and George Alangaden, MD1, (1)Infectious Diseases, Henry Ford Hospital, Detroit, MI, (2)Microbiology and Pathology, Henry Ford Hospital, Detroit, MI


M. Miceli, None

M. Alexis, None

L. Samuel, None

M. Ramesh, None

G. Alangaden, None

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