Mycobacterium marinum infection follows traumatic inoculation while the exposed skin is in an aqueous environment, whether a fish tank, swimming pool, or brackish water. It is characterized clinically by an inflammatory verrucous or crusted lesion at the inoculation site, and in some cases lymphangitic spread.
Causes of Mycobacterium Marinum Infection
The cause is infection with M marinum.
- Exposure of traumatized skin to affected aqueous environments (fish tanks) is the leading predisposing factor.
- Individuals who are consistently exposed to the organism are more likely to develop the infection.
- Hosts who are immunocompromised are also at increased risk.
Symptoms of Mycobacterium Marinum Infection
- Lymphadenopathy may be present.
- An erythematous or bluish 0.5- to 3-cm papule or nodule develops at the inoculation site, which is the upper extremity in 90% of cases.
- Patients may have deeper involvement, with tenosynovitis bursitis, septic arthritis.
Diagnosis
History of trauma in an aqueous environment, clinical findings, confirmed by isolation of M.marinum on culture.
Treatment
Antibiotics Empirical Treatment Drug of first choice: minocycline, 100 mg bid. Alternative drugs: trimethoprim-sulfamethoxazole, rifampin, clarithromycin.
M. marinum Isolated and Sensitivities Determined If sensitivities show drug resistance, then rifampin (600 mg qid) and ethambutol (800 mg qid) is an effective combination in 90% of patients and should be given in sporotrichoid form of infection.
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