Investigation of Potential Reservoirs of Non-Tuberculous Mycobacteria in a European Sea Bass (Dicentrarchus labrax) Farm

Abstract

Fish mycobacteriosis is a widespread global problem caused by species of non-tuberculous mycobacteria (NTM). Mycobacterium marinum is one of the species most often involved in disease episodes of aquarium and farmed fish. Since there is currently no available effective therapy or vaccine, a prompt search for routes of entry is key to limiting the damage induced by the disease. Here we report a case of mycobacteriosis follow up in a European sea bass (Dicentrarchus labrax) farm located in Northern Italy, in which environmental samples and newly added fish batches were analyzed. Samples from fish present on the farm, sediment, and periphyton all resulted positive for M. marinum, whereas the new fish batches and the water samples resulted negative. The environmental resistance of NTM (alcohol-acid resistance, biofilm formation) and the lack of prophylactic and therapeutic strategies make these diseases difficult to manage. Prompt identification of biotic and abiotic reservoirs, combined with good zootechnical hygiene practices, are the most effective measures to control fish mycobacteriosis in intensive farms.

Recovery of Mycobacteria from Heavily Contaminated Environmental Matrices

“…From extrapulmonary infections, lymphadenitis in children predominated over the last three years [ 10 ]. The slow-growing M. marinum is the causal agent of chronic systemic infections in fish and it occasionally causes granulomatous skin lesions involving the hands, forearms, elbows, and knees in humans reporting contact with aqueous environments [ 11 , 12 ].…”

Draft Genome Sequences of 25 Mycobacterium marinum Strains Isolated from Animals and Environmental Components in Aquaria and an Aquaculture Farm

“… Mycobacterium marinum is a nontuberculous mycobacterium (NTM) and zoonotic pathogen that has been isolated from mammals, fish, amphibians, reptiles, birds, invertebrates, and protists ( 1 – 8 ); M. marinum is also widely distributed in nature, especially in aquatic environments ( 9 – 13 ). We sequenced the genomes of 25 strains of M. marinum that had been isolated from vertebrates, invertebrates, and environmental components in aquaria and an aquaculture farm in Japan between 2015 and 2020.…”

Core single nucleotide polymorphism analysis reveals transmission of Mycobacterium marinum between animal and environmental sources in two aquaria

“…Mycobacterium marinum is ubiquitous in aquatic environments such as sand, water, biofilms, periphytons, and plants in the natural habitats (pond, river, and sea) and rearing environments (tanks at individual homes, aquaria, and aquaculture farms) (Makovcova et al, 2014; Mason et al, 2016; Mugetti et al, 2021; Slany et al, 2014; Yanong et al, 2010). This evidence leads to the hypothesis that a wide variety of animal and environmental sources could be involved in the transmission of M. marinum .…”