Pathology attributed to Mycobacterium chelonae infection among farmed and laboratory-infected Atlantic salmon Salmo salar

Bruno, D. W.; Griffiths, J.S.; Mitchell, C. G.; Wood, B. P.; Fletcher, Z. J.; Drobniewski, Francis; Hastings, T. S.

doi:10.3354/dao033101

Cited by 72 publications

(93 citation statements)

References 12 publications

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“…Typically, mycobacterial isolates from fish have included rapidly growing species such as Mycobacterium fortuitum, Mycobacterium marinum, Mycobacterium chelonae, and Mycobacterium poriferae (1,3,4,5,7,10,14,16,19,21,22,24). This is the first report of an M. triplex-like organism being isolated from fish.…”

Section: Discussionmentioning

confidence: 88%

Granulomatous Skin Lesions in Moray Eels Caused by a NovelMycobacteriumSpecies Related toMycobacterium triplex

et al. 2001

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An outbreak of granulomatous dermatitis was investigated in a captive population of moray eels. The affected eels had florid skin nodules concentrated around the head and trunk. Histopathological examination revealed extensive granulomatous inflammation within the dermis and subcutaneous fascial plane between the fat and axial musculature. Acid-fast rods were detected within the smallest lesions, which were presumably the ones that had developed earliest. Eventually, after several months of incubation at room temperature, a very slowly growing acid-fast organism was isolated. Sequencing of the 16S rRNA gene identified it as a Mycobacterium species closely related (0.59% divergence) to M. triplex, an SAV mycobacterium. Intradermal inoculation of healthy green moray eels with this organism reliably reproduced the lesion. Experimentally induced granulomatous dermatitis appeared within 2 weeks of inoculation and slowly but progressively expanded during the 2 months of the experiment. Live organisms were recovered from these lesions at all time points, fulfilling Koch's postulates for this bacterium. In a retrospective study of tissues collected between 1993 and 1999 from five spontaneous disease cases, acid-fast rods were consistently found within lesions, and a nested PCR for the rRNA gene also demonstrated the presence of mycobacteria within affected tissues.Cases of proliferative skin disease have occurred sporadically and persistently within captive exhibit populations of moray eels across the country (Ray Davis, personal communication). Typically, affected eels have florid, soft, gelatinous grey-and tan-colored masses at various locations on the body surface and within the oral and nasal cavities. In this study, a disease outbreak that has been ongoing in an exhibit since it opened in 1992 was investigated. The exhibit consists of a 226,000-gallon synthetic seawater habitat with fiberglass-reinforced concrete and plastic (urethane) structural elements designed to reproduce a coral reef habitat. The exhibit initially contained approximately 500 green moray (Gymnothorax funebris) and spotted moray (Gymnothorax moringa) eels. Cases were first observed during the collection and quarantine of wild moray eels caught near the Florida Keys, from October 1991 through June 1992, prior to the exhibit's opening. No animals with detectable lesions were collected, nor were any put on display. Even so, clinical cases began to develop in the exhibit shortly after opening. This paper summarizes histopathologic and microbiologic data from a series of cases and reports the association of acid-fast bacteria with ulcerative granulomatous dermatitis, the isolation of a novel Mycobacterium species, and the fulfillment of Koch's postulates for this organism. MATERIALS AND METHODS Source of animals.Captive specimens were obtained from among eels housed in the exhibit under study. Two green moray eels were selected for complete necropsy and diagnostic evaluation because they had several small (diameter, Ͻ10 mm) lesions. These small lesi...

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Section: Discussionmentioning

confidence: 88%

Granulomatous Skin Lesions in Moray Eels Caused by a NovelMycobacteriumSpecies Related toMycobacterium triplex

et al. 2001

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“…Interestingly, the island is putatively duplicated in the M. salmoniphilum strains. This bacterium is a recognized pathogen of salmonids, based on both laboratory transmission studies (1) and field observations (8,10). The in vivo and in vitro growth of these strains of mycobacteria suggest that the genes making up this PI should be studied further for their role in the virulence of EM.…”

Section: Discussionmentioning

confidence: 99%

Species of Environmental Mycobacteria Differ in Their Abilities To Grow in Human, Mouse, and Carp Macrophages and with Regard to the Presence of Mycobacterial Virulence Genes, as Observed by DNA Microarray Hybridization

Harriff

Kent

et al. 2008

Appl Environ Microbiol

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There are many species of environmental mycobacteria (EM) that infect animals that are important to the economy and research and that also have zoonotic potential. The genomes of very few of these bacterial species have been sequenced, and little is known about the molecular mechanisms by which most of these opportunistic pathogens cause disease. In this study, 18 isolates of EM isolated from fish and humans (including strains of Mycobacterium avium, Mycobacterium peregrinum, Mycobacterium chelonae, and Mycobacterium salmoniphilum) were examined for their abilities to grow in macrophage lines from humans, mice, and carp. Genomic DNA from 14 of these isolates was then hybridized against DNA from an M. avium reference strain, with a custom microarray containing virulence genes of mycobacteria and a selection of representative genes from metabolic pathways. The strains of EM had different abilities to grow within the three types of cell lines, which grouped largely according to the host from which they were isolated. Genes identified as being putatively absent in some of the strains included those with response regulatory functions, cell wall compositions, and fatty acid metabolisms as well as a recently identified pathogenicity island important to macrophage uptake. Further understanding of the role these genes play in host specificity and pathogenicity will be important to gain insight into the zoonotic potential of certain EM as well as their mechanisms of virulence.

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“…Chronic disease is most commonly observed and is characterized by granulomatous inflammation that may affect all host tissues. External clinical signs include scale loss, dermal ulceration, spinal defects, emaciation, and ascites (5,6,16,25,31).Mycobacteriosis in Chesapeake Bay striped bass (Morone saxatilis) was first observed in 1997 from histologic findings of acid-fast bacilli in granulomatous lesions (W. Vogelbein, unpublished data). Since the initial finding, surveys have demonstrated a very high prevalence of this disease in Chesapeake Bay striped bass, exceeding 50% in many samples (8,17).…”

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confidence: 99%

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confidence: 99%

Quantitative PCR Assay for Mycobacterium pseudoshottsii and Mycobacterium shottsii and Application to Environmental Samples and Fishes from the Chesapeake Bay

Gauthier

Reece

Xiao

et al. 2010

Appl Environ Microbiol

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Striped bass (Morone saxatilis) in the Chesapeake Bay are currently experiencing a very high prevalence of mycobacteriosis associated with newly described Mycobacterium species, Mycobacterium pseudoshottsii and M. shottsii. The ecology of these mycobacteria outside the striped bass host is currently unknown. In this work, we developed quantitative real-time PCR assays for M. pseudoshottsii and M. shottsii and applied these assays to DNA extracts from Chesapeake Bay water and sediment samples, as well as to tissues from two dominant prey of striped bass, Atlantic menhaden (Brevoortia tyrannus) and bay anchovy (Anchoa mitchilli). Mycobacterium pseudoshottsii was found to be ubiquitous in water samples from the main stem of the Chesapeake Bay and was also present in water and sediments from the Rappahannock River, Virginia. M. pseudoshottsii was also detected in menhaden and anchovy tissues. In contrast, M. shottsii was not detected in water, sediment, or prey fish tissues. In conjunction with its nonpigmented phenotype, which is frequently found in obligately pathogenic mycobacteria of humans, this pattern of occurrence suggests that M. shottsii may be an obligate pathogen of striped bass.Mycobacteriosis is a common disease affecting a large variety of wild and aquacultured fishes worldwide (9). Chronic disease is most commonly observed and is characterized by granulomatous inflammation that may affect all host tissues. External clinical signs include scale loss, dermal ulceration, spinal defects, emaciation, and ascites (5,6,16,25,31).Mycobacteriosis in Chesapeake Bay striped bass (Morone saxatilis) was first observed in 1997 from histologic findings of acid-fast bacilli in granulomatous lesions (W. Vogelbein, unpublished data). Since the initial finding, surveys have demonstrated a very high prevalence of this disease in Chesapeake Bay striped bass, exceeding 50% in many samples (8,17). Concomitantly with detection of high prevalence, tag recapture analysis has indicated that natural, nonfishing mortality of Chesapeake Bay striped bass has increased since 1999 (13), and modeling of apparent prevalence data has indicated that some mortality is associated with disease (8). Because the striped bass is an ecologically and economically important finfish along the U.S. Atlantic coast, the high prevalence of this disease creates considerable concern about the continuing health of the resource.Mycobacteriosis of fishes has traditionally been considered to be caused by Mycobacterium marinum, M. fortuitum, or M. chelonae; however, the recognized diversity of Mycobacterium spp. infecting fishes has increased markedly in recent years (9).To date, neither M. fortuitum nor M. chelonae have been isolated from internal tissues of striped bass in the Chesapeake Bay, and M. marinum has been cultured from only a small fraction (3%) of fish (20). Instead, a variety of slow-growing mycobacteria have been isolated, dominated by the recently described species M. pseudoshottsii and M. shottsii (9,(20)(21)(22). The 16S rRNA gene sequenc...

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Pathology attributed to Mycobacterium chelonae infection among farmed and laboratory-infected Atlantic salmon Salmo salar

Cited by 72 publications

References 12 publications

Granulomatous Skin Lesions in Moray Eels Caused by a NovelMycobacteriumSpecies Related toMycobacterium triplex

Granulomatous Skin Lesions in Moray Eels Caused by a NovelMycobacteriumSpecies Related toMycobacterium triplex

Species of Environmental Mycobacteria Differ in Their Abilities To Grow in Human, Mouse, and Carp Macrophages and with Regard to the Presence of Mycobacterial Virulence Genes, as Observed by DNA Microarray Hybridization

Quantitative PCR Assay for Mycobacterium pseudoshottsii and Mycobacterium shottsii and Application to Environmental Samples and Fishes from the Chesapeake Bay

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