Mycobacterium marinum skin infection

Mycobacterium marinum lives in aquatic environments, where it causes disease in many poikilodermic fish species living in fresh or saltwater; the organism has a wide geographic distribution in the water world. The first report of a mycobacterium isolated in fish (very likely M. marinum) is attributed to Bataillon and Coll, who isolated acid-fast bacilli, named M. piscium, in 1897, from a tuberculous lesion of a common carp (Cyprinus carpio). Then in 1926 it was isolated and identified by Aronson from tubercles in various organs of marine fish found dead in the Philadelphia Aquarium. Initially M. marinum was thought to infect fishes only and was named accordingly, but it is now known to be a ubiquitous species. The original freshwater isolate of M. piscium was quite possibly a variant of M. marinum. Other marine Mycobacterium species have been described in the literature, such as M. platypoecilus, M. anabanti, and M. balnei; however, comparative cultural, morphological, and pathogenic data suggest that they were all synonymous with M. marinum. M. marinum was identified as a causal agent of human disease only in 1951, when it was identified from skin lesions in swimmers in a contaminated swimming pool in the city of Orebro, Sweden. The term “swimming pool granuloma” was coined to denote these lesions and the causal agent was classified as M. balnei but then, when the two mycobacteria were later seen to be identical, as M. marinum.