Complete genome sequence of the type strain of Mycobacterium montefiorense, strain ATCC BAA-256.

Mycobacterium montefiorense, a nontuberculous mycobacterium, is a causative agent of mycobacteriosis in aquatic animals, its type strain M. montefiorense ATCC BAA-256 being isolated from a moray eel. In this study, we report the complete ATCC BAA-256 genome sequence with a 5,693,452-bp-containing circular chromosome, 65.2% GC content, and 5,407 coding sequences.

Non-tuberculous mycobacterial disease associated with Mycobacterium montefiorense in salamanders.

Introduction: Mycobacterium montefiorense is one of the causes of non-tuberculous mycobacterial infections in moray eels and salamanders. Although M. montefiorense infection could be a threat to salamanders, little information is available regarding this pathogen and associated infection. This study aimed to provide fundamental information regarding M. montefiorense and its infection in salamanders. Methods: Nine M. montefiorense strains isolated from three species of salamanders, namely, Japanese black salamander (Hynobius nigrescens), Hakuba salamander (H. hidamontanus), and Tohoku hynobiid salamander (H. lichenatus), between 2010 and 2018, were characterized based on phenotypic and genetic examination. We also pathologically observed salamanders infected with the M. montefiorense strains, including Hakuba salamanders and Tohoku hynobiid salamanders. Results: The microbiological and chemical characteristics of the M. montefiorense salamander and an eel strain (reference strain) matched. Susceptibility testing for antimicrobials suggested that clarithromycin may be effective. Regarding disinfectants, phtharal, peracetic acid, glutaral, sodium hypochlorite, and benzalkonium chloride may be effective. Phylogenetic analyses revealed that the strains isolated from salamanders in 2014 and 2018 were genetically closely related, which could indicate an outbreak. The main gross findings in infected salamanders include skin ulcerative lesions or nodules in the enlarged liver. Microscopically, multifocal to coalescent granulomatous lesions composed of massive macrophages containing numerous acid-fast bacilli were prominently observed in the liver. Conclusion: This study contributes to our understanding of the genetic diversity and phenotypic characteristics of M. montefiorense, as well as the pathology of the infection.

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

Mycobacterium marinum is a slow-growing, photochromogenic nontuberculous mycobacterium, which can cause mycobacteriosis in various animals, including humans. Several cases of fish mycobacteriosis have been reported to date. Mycobacterium marinum has also been isolated from aquatic environmental sources such as water, sand, biofilms, and plants in the natural environments. Hence, we hypothesized that a wide variety of sources could be involved in the transmission of M. marinum. In this study, we tested this hypothesis by isolating M. marinum from various sources such as fish, invertebrates, seagrass, periphytons, biofilms, sand, and/or water in two aquaria in Japan and conducting a phylogenetic analysis based on single-nucleotide polymorphisms (SNPs) using whole-genome sequences of the isolated strains. The analysis revealed that the strains from animal and environmental sources belonged to the same clusters. This molecular-based study epidemiologically confirmed that various sources, including fish, invertebrates, and environmental sources, could be involved in transmission of M. marinum in a closed-rearing environment. This is the first report where M. marinum was isolated from different sources, and various transmission routes were confirmed in actual cases, which provided essential information to improve the epidemiology of M. marinum.

Draft Genome Sequence of a Mycobacterium chelonae subsp. bovis Strain Isolated from a Baikal Seal (Pusa sibirica) in Captivity.

Mycobacterium chelonae is a nontuberculous mycobacterium that causes infections in various animals, including humans. In this study, we report the draft genome sequence of M. chelonae subsp. bovis strain NJB1701, which was isolated from a Baikal seal (Pusa sibirica) in captivity in Japan.

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

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.

Complete Genome and Partial Megaplasmid Sequences of Mycobacterium pseudoshottsii Strain NJB1907-Z4, Isolated from an Aquarium-Reared Japanese Sardine (Sardinops melanostictus) in Japan.

Mycobacterium pseudoshottsii, a slow-growing nontuberculous mycobacterium, has been isolated from wild and cultured fish. We report here the complete genome and partial megaplasmid sequences of a strain isolated from an aquarium-reared Japanese sardine (Sardinops melanostictus) in Japan, M. pseudoshottsii NJB1907-Z4.

A case of mycobacteriosis associated with Mycobacterium pseudoshottsii in aquarium-reared fish in Japan.

In 2019, several aquarium-reared fish died at a sea life park in Japan. Necropsy revealed micronodules on the spleen in the dotted gizzard shad (Konosirus punctatus). Seven of 16 fish exhibited microscopic multifocal granulomas associated with acid-fast bacilli in the spleen, kidney, liver, alimentary tract, mesentery, gills, and/or heart. Bacterial cultures yielded isolates from the dotted gizzard shad and a Japanese sardine (Sardinops melanostictus). Microbiological and molecular biological examinations revealed the isolates as Mycobacterium pseudoshottsii. To our knowledge, this is the first isolation of M. pseudoshottsii from aquarium-reared fish.

Draft Genome Sequences of Eight Mycobacterium montefiorense Strains Isolated from Salamanders in Captivity.

Mycobacterium montefiorense is a nontuberculous mycobacterium that causes infections in fish and salamanders. Here, we report annotated draft genome sequences of eight strains that were isolated in 2014 and 2018 from salamanders reared in an aquarium in Japan.

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

Mycobacterium marinum is a ubiquitous nontuberculous mycobacterium that causes infections in various animals. Here, we report the annotated draft genome sequences of 25 strains isolated from vertebrates, invertebrates, and environmental components in aquaria and an aquaculture farm in Japan, sampled between 2015 and 2020.