Infection of the upper extremity by Mycobacterium marinum in a 3-year-old boy--diagnosis by 16S-rDNA analysis

Sporotrichoid lymphocutaneous pattern in a fish-merchant under immunosuppressant medications: Clues to differential diagnoses

Sporotrichoid-lymphocutaneous-pattern is classically seen in sporotrichosis, though also present in other infections like atypical mycobacteriosis and leishmaniasis. Cutaneous atypical mycobacterial infection presents as localized lesions in immunocompetent and is widespread in immunosuppressed patients. Here, we present a case of sporotrichoid-lymphocutaneous infection due to atypical mycobacteria, in a fish-seller under immunosuppressants.

Fish tank granuloma caused by Mycobacterium marinum

Introduction

Mycobacterium marinum causes skin and soft tissue, bone and joint, and rare disseminated infections. In this study, we aimed to investigate the relationship between treatment outcome and antimicrobial susceptibility patterns. A total of 27 patients with M. marinum infections were enrolled.

Methods

Data on clinical characteristics and therapeutic methods were collected and analyzed. We also determined the minimum inhibitory concentrations of 7 antibiotics against 30 isolates from these patients.

Results

Twenty-seven patients received antimycobacterial agents with or without surgical debridement. Eighteen patients were cured, 8 failed to respond to treatment, and one was lost to follow-up. The duration of clarithromycin (147 vs. 28; p = 0.0297), and rifampicin (201 vs. 91; p = 0.0266) treatment in the cured patients was longer than that in the others. Surgical debridement was performed in 10 out of the 18 cured patients, and in 1 of another group (p = 0.0417). All the 30 isolates were susceptible to clarithromycin, amikacin, and linezolid; 29 (96.7%) were susceptible to ethambutol; 28 (93.3%) were susceptible to sulfamethoxazole; and 26 (86.7%) were susceptible to rifampicin. However, only 1 (3.3%) isolate was susceptible to doxycycline.

Discussion

Early diagnosis of the infection and appropriate antimicrobial therapy with surgical debridement are the mainstays of successful treatment. Clarithromycin and rifampin are supposed to be more effective agents.

Treatment of Mycobacterium marinum cutaneous infections

Mycobacterium marinum is a non-tuberculous mycobacterium found in non-chlorinated water, with worldwide prevalence. It is the most common atypical Mycobacterium that causes opportunistic infection in humans. It presents as a solitary, red-to-violaceous plaque or nodule with an overlying crust or verrucous surface, or as inflammatory nodules or abscesses, usually in a sporotrichotic type of distribution. Deep infections may also occur. Although diagnosis is confirmed by isolation and identification of the organism in practice diagnosis remains largely presumptive based on clinicohistological features and the response to treatment. Polymerase chain reaction allows the routine early detection of the organism from a biopsy specimen. In the near future, it seems possible that histopathological examination might be greatly assisted by the rapidly improving possibilities with in vivo imaging. There have been many therapeutic modalities used effectively in the treatment of M. marinum infections. Spontaneous remission has also been reported in untreated infections and in immunocompetent hosts. However, there is no proven treatment of choice because M. marinum is naturally multi-drug resistant species and treatment is based primarily on the personal experience and preference of individual investigators, without the benefit of large studies. In superficial cutaneous infections minocycline, clarithromycin, doxycycline and trimethoprim-sulfamethoxazole as monotherapy are effective treatment options, but drug resistance varies and thereby combination therapy usually of two drugs may be required. Ciprofloxacin has shown considerable effectiveness. In cases of severe infections, including those with a sporotrichoid distribution pattern, a combination of rifampicin and ethambutol seems to be the recommended regimen. The use of isoniazid, streptomycin and pyrazinamide as empirical treatment options should be avoided. Surgical treatment is not usually recommended and must be cautiously applied. Cryotherapy, X-ray therapy, electrodesiccation, photodynamic therapy and local hyperthermic therapy have been reported as effective therapeutic alternatives. M. marinum infection should always be included in the differential diagnosis of all cases with poor-healing wounds in upper extremities and a history of exposure to aquariums.

Masquerading Mycobacterium: Plastic surgeon to the rescue

A patient with a Mycobacterium marinum infection of the hand is described. The present case illustrates that M marinum infection may mimic common skin conditions such as eczema, and fungal and parasitic infestations. Key elements in the diagnosis and management of this infection are a high index of suspicion, a detailed history of recreational or occupational exposure to exotic fish, tissue biopsy, wound culture and prompt empirical antibiotic therapy. Once in vitro organism sensitivities are obtained, antibiotic treatment may last for up to 24 months. Surgical drainage and debridement are an important supplement to antimicrobial therapy when subcutaneous structures are involved, as in the present report. Invasive digital and hand infections can rapidly result in permanent residual stiffness, deformity and loss of function; therefore, it is important to raise awareness of the condition among those considered to be at risk.

Mycobacterium marinum infections

Mycobacterium marinum is a saprophytic mycobacteria capable of causing soft tissue infection in humans, usually acquired by inoculation. As with other mycobacterial infections, diagnosis may be difficult and recent developments in molecular biology are also being applied to atypical mycobacteria such as Mycobacterium marinum.