Local and Disseminated Infections Caused by Mycobacterium marinum: An Unusual Cause of Subcutaneous Nodules

Clinical Implications for the Timely Diagnosis of Mycobacterium marinum in the Age of Biologic Therapy: A Case Report and Review of the Literature

Mycobacterium marinum infections typically present as cutaneous nodular lesions with a sporotrichoid lymphatic spread on extensor surfaces of extremities. The natural history of this infection can be altered if the host is immunosuppressed, leading to disseminated presentations. A detailed exposure history and high degree of suspicion for this indolent pathogen are often required for the correct diagnosis of this disease. We present a case of a 67-year-old male misdiagnosed with seronegative rheumatoid arthritis presenting with rheumatic nodules. Initiation of chronic immunosuppressant therapy including biologic monoclonal antibodies resulted in the exacerbation of initially localized disease to broadly disseminated lymphatic, joint, and myotendinous granulomatous disease and led to delay in the correct diagnosis. Cessation of immunosuppressants, with a prolonged course of antimicrobial therapy and multiple surgical debridements were required for cure.

Osteomyelitis Infection of Mycobacterium marinum: A Case Report and Literature Review

Mycobacterium marinum (M. marinum) is a ubiquitous waterborne organism that grows optimally at temperatures around 30°C. It is a nontuberculous Mycobacterium found in nonchlorinated water with worldwide prevalence. It is the most common atypical Mycobacterium that causes opportunistic infection in humans. M. marinum can cause superficial infections and localized invasive infections in humans, with the hands being the sites most frequently affected. It can cause skin lesions, which are either single, papulonodular lesions, confined to an extremity, or may resemble cutaneous sporotrichosis. This infection can also cause deeper infections including tenosynovitis, bursitis, arthritis, and osteomyelitis. Disseminated infections and visceral involvements have been reported in immunocompromised patients. We here report a case of severe deep soft tissue infection with necrotizing fasciitis and osteomyelitis of the left upper extremity (LUE) caused by M. marinum in an immunocompromised patient.

Necrotizing Soft Tissue Infection Occurring after Exposure to Mycobacterium marinum

Cutaneous infections caused by Mycobacterium marinum have been attributed to aquarium or fish exposure after a break in the skin barrier. In most instances, the upper limbs and fingers account for a majority of the infection sites. While previous cases of necrotizing soft tissue infections related to M. marinum have been documented, the importance of our presenting case is to illustrate the aggressive nature of M. marinum resulting in a persistent necrotizing soft tissue infection of a finger that required multiple aggressive wound debridements, followed by an amputation of the affected extremity, in order to hasten recovery.

Rare diagnosis of nodular lymphangitis caused by Mycobacterium marinum: MDCT imaging findings

Mycobacterium marinum is an atypical mycobacterium that usually causes a solitary nodule on the hand (“fish tank granuloma”) or less commonly, secondary erythematous channels and nodules spread along lymphatic drainage of the extremity, mimicking sporothricoid skin lesions of nodular lymphangitis. This report presents a case of this rare entity, a nodular lymphangitis caused by Mycobacterium marinum. Multidetector computed tomography (MDCT) imaging was very useful in determining the morphology (cellulitis with a few small subcutaneous nodules and channels) and the extension of the lesion.

[Infections due to Mycobacterium marinum: a review]

Mycobacterium marinum belongs to the non-tuberculous or "atypical" mycobacteria. The reservoirs for these ubiquitous and slowly growing bacteria are both fresh water and salt water. In particular, aquaria should be considered as important source of hobby-related infections especially of fingers, hands and forearms. Affected are both immunosuppressed patients and persons with an intact immune system. Distinctive are erythematous plaques and nodules with tendency for hyperkeratosis, crusting, and superficial ulcerations, sometimes as sporotrichoid lymphocutaneous infection. The histology shows non-caseation granulomas containing epithelioid cells and Langhans giant cells. Using the Ziehl Neelsen staining, typical acid-fast rods are not always detectable. The molecular biological detection of mycobacterial DNA using polymerase chain reaction represents the standard method of diagnosis. Cryotherapy is frequently used as first treatment. For the often long-term tuberculostatic therapy, rifampicin, ethambutol, and clarithromycin are the most used agents.

Upper extremity Mycobacterium marinum infection

Mycobacterium marinum is the cause of opportunistic infections in man. Although its clinical presentation is usually cutaneous, osteoarticular infections are not rare and should be rapidly diagnosed. Orthopaedic surgeons may have to manage a patient with this mycobacterial infection and should be able to make this diagnosis based on information about the patient's history and clinical criteria. Lesions develop from a skin wound, with a single nodule or a bright purplish-red patch with papules; they also may be inflamed or may abscess. Secondary lesions may develop as the disease progresses. Aquatic exposure is the most important factor to look for. We report three cases of this infection with a delayed diagnosis. Response to treatment and an absence of complications are correlated with an early diagnosis.