Genital mycobacteriosis caused by Mycobacterium marinum detected in two captive sharks by peptide nucleic acid–fluorescence in situ hybridization

• Published in: Journal of fish diseases 2023-01, Vol.46 (1), p.47-59
• Main Authors: Inohana, Mari, Komine, Takeshi, Tanaka, Yoshiaki, Kurata, Osamu, Wada, Shinpei
• Format: Article
• Language: English
• Subjects: Animals; Aquaria; Aquarium fishes; Aquariums; Aquatic environment; Carnivorous animals; Connective tissue; Connective tissues; DNA sequences; DNA sequencing; elasmobranch; Fish Diseases; Fluorescence; Fluorescence in situ hybridization; Genitalia; Gonads; Granulomas; Heat shock proteins; Heterodontus japonicus; Histopathology; Hsp65 protein; Husbandry diseases; Hybridization; In Situ Hybridization, Fluorescence - veterinary; Localization; Marine fishes; Marine molluscs; Mycobacteriosis; Mycobacterium marinum; Mycobacterium marinum - genetics; Necrosis; Nucleic acids; Nucleotide sequence; PCR; Peptide nucleic acids; Peptide Nucleic Acids - genetics; Peptides; PNA‐FISH; Polymerase chain reaction; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sharks; Sphyrna lewini; zoonosis
• ISSN: 0140-7775; 1365-2761
• DOI: 10.1111/jfd.13716

Mycobacterium marinum is a prevalent nontuberculous mycobacterium (NTM)‐infecting teleosts. Conversely, little is known about mycobacteriosis in elasmobranchs, and M. marinum infection has never been reported from the subclass. This study investigated the histopathological characteristics and localization of this mycobacterium through molecular analysis of two captive sharks, a scalloped hammerhead Sphyrna lewini and a Japanese bullhead shark Heterodontus japonicus, exhibited in the same aquarium tank. We detected genital mycobacteriosis caused by M. marinum infection using molecular analyses, including polymerase chain reaction (PCR) and DNA sequencing targeting the 60 kDa heat‐shock protein gene (hsp65), and peptide nucleic acid–fluorescence in situ hybridization (PNA‐FISH) targeting the 16S rRNA gene. Both sharks showed granulomas in connective tissues of the gonads without central necrosis or surrounding fibrous capsules, which is unlike the typical mycobacterial granulomas seen in teleosts. This study reveals that elasmobranchs can be aquatic hosts of M. marinum. Because M. marinum is a representative waterborne NTM and a potential zoonotic agent, cautious and intensive research is needed to overcome a lack of data on the relationship between NTM and the aquatic environment in association with this subclass of Chondrichthyes.