1384. Mycobacterium marinum Infection: 21 Years of Experience at a Tertiary-Care Hospital

BACKGROUND: Mycobacterium marinum is a slow-growing, non-tuberculous mycobacterium responsible for skin and soft-tissue infections (SSTIs), tenosynovitis, and osteomyelitis (OM). We conducted a retrospective study describing the risk, clinical course, and outcome of M. marinum infection. METHODS: Adult patients with culture-confirmed M. marinum infections were identified from the mycology laboratory at Mayo Clinic, Rochester from January 1998 to December 2018. M. marinum infection was defined as uncomplicated (limited to SST) and complicated (tenosynovitis, OM, or disseminated). RESULTS: Forty-six cases of culture-confirmed infection with M. marinum were included (Table 1). Only 16 cases (35%) reported a water exposure and 22 (48%) involved finger and/or hand trauma. The median time to diagnosis was 3.6 months. Most patients (76%) presented with uncomplicated M. marinum infection with skin lesions mainly localized in the upper limb (Table 2). QuantiFERON and PPD were positive in 4 (8%) and 2 (4%) cases, respectively. Granulomatous inflammation and positive special stains were noted in 34 (74%) and 11 (24%) cases, respectively. Cases with complicated M. marinum infection had a longer duration of symptoms and length of treatment (P < 0.05) (Table 3). Prior to diagnosis, 63% of patients received at least one antibiotic for bacterial SSTIs. More than 50% of the patients diagnosed with M. marinum received a one drug regimen and 8% did not initiate therapy. Median treatment duration was 4.4 months. Twenty-six cases (56%) had susceptibilities performed and treatment modifications were made in 10 cases (38%). From the patients that started therapy, 73% completed therapy and 33% were lost to follow up. Cured was achieved in 87% of cases that completed therapy, 2 cases (6%) had a recurrence, and only one patient with active malignancy had a positive blood culture and died. Twelve (44%) and 10 cases (37%) were cured with one and two-drug regimens, respectively. CONCLUSION: Most patients with M. marinum infection present as an uncomplicated infection in the upper limb. Classical exposure was only suspected in a third of the cases. Patients with complicated M. marinum infection had a prolonged duration of symptoms and lengthy treatment. Most patients were successfully treated with a one and two-drug regimen. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.