An evaluation of the prevalence of Mycobacterium marinum in aquaria and its impact on man

Abstract

Mycobacterium marinum is a pathogenic organism normally found in aquaria and is the cause of fish tuberculosis. However, it also has the zoonotic potential to affect man. Granulomatous lesions are the common presenting manifestation and although this infection is generally cutaneous, it can disseminate if not treated. Although research about this organism does exist, studies have not investigated aquarium water itself as the probable source of infection. This dissertation aims to evaluate the prevalence of Mycobacterium marinum in aquaria and its impact on man. Two-hundred and thirty-five (235) specimens of aquarium water were collected to determine the prevalence of Mycobacterium marinum in Malta. All of these were treated to concentrate the bacterial load and enhance the possibility of mycobacterial isolates using standard bacteriological techniques. Phenotypic and genotypic tests were used in conjunction to fully identify Myco. marinum down to species level. An overall prevalence of 1.3% was subsequently found. Although the prevalence is low, this confirms its presence in aquarium water and hence, its possible transmission to man. A greater awareness should be awakened in the aquarist community. Moreover, a microbiological diagnosis should always be done in cases of infection by isolating the organism and determining its antibiotic sensitivity pattern.