Mycobacterium marinum infections in Denmark from 2004 to 2017: A retrospective study of incidence, patient characteristics, treatment regimens and outcome

Inge K Holden,Isik Somuncu Johansen,Christian Wejse,Michala Kehrer,Aase B Andersen,Erik Svensson

doi:10.1038/s41598-018-24702-7

Abstract

Mycobacterium marinum (M. marinum) is a slowly growing nontuberculous mycobacterium. The incidence of M. marinum infections in Denmark is unknown. We conducted a retrospective nationwide study including all culture confirmed cases of M. marinum from 2004 to 2017 in Denmark. All available medical records were reviewed. Demographics, clinical characteristics, and treatment regiments were analyzed. Fifty-five patients were identified, 40 (72.7%) were men with a median age of 50 years. Aquatic exposure was reported by 48 (90.6%) of the patients. Site of infection was upper extremities in 49 (92.5%) patients and 49 (92.5%) had superficial infection. The median time from symptom presentation to diagnosis was 194 days. All patients received antibiotics. Median time of treatment duration among all patients was 112 days. Treatment outcome was classified as improved in 40 (75%), improved with sequela in 4 (7.6%) patients and only 3 patients (3.8%) were classified as failed. Infection with M. marinum is rare and there is a long delay from symptom manifestation to diagnosis. The infection is predominantly related to aquatic exposure. M. marinum should be a differential diagnose in patients with slow-developing cutaneous elements and relevant exposure. Treatment outcomes are overall good and severe sequela are rare.

Highlights

Mycobacterium marinum (M. marinum) is a slowly growing nontuberculous mycobacterium, which was first isolated from marine fish
From January 1st, 2004 to May 31st, 2017, we identified 55 patients with culture verified M. marinum infections
Almost all patients had a history of aquatic exposure (90.6%), the most common exposure came from maintenance of fish tanks

Summary

Introduction

Mycobacterium marinum (M. marinum) is a slowly growing nontuberculous mycobacterium, which was first isolated from marine fish. M. marinum is found in non-disinfected salt- and freshwater reservoirs such as swimming pools and fish tanks[1,2]. Most infections with M. marinum are superficial skin infections characterized by granuloma and lymphangitis known as “fish tank granuloma” or “swimming pool granuloma”; the infection may spread to deeper tissue causing tendinitis, arthritis and osteomyelitis[3]. The incidence of M. marinum infections in Denmark is unknown. Recent studies from The United States reported an increase in incidence of cutaneous nontuberculous mycobacterial infections and M. marinum infections in particular[1,5]. This study was conducted to provide information regarding the incidence, clinical features, treatment regimens and clinical outcome of patients infected with M. marinum infections in Denmark

Methods

Results

Conclusion