Genomics of Tenacibaculum Species in British Columbia, Canada (original) (raw)
Related papers
Genome Biology and Evolution, 2018
The genus Tenacibaculum encompasses several species pathogenic for marine fish. Tenacibaculum dicentrarchi and "Tenacibaculum finnmarkense" (Quotation marks denote species that have not been validly named.) were retrieved from skin lesions of farmed fish such as European sea bass or Atlantic salmon. They cause a condition referred to as tenacibaculosis and severe outbreaks and important fish losses have been reported in Spanish, Norwegian, and Chilean marine farms. We report here the draft genomes of the T. dicentrarchi and "T. finnmarkense" type strains. These genomes were compared with draft genomes from field isolates retrieved from Chile and Norway and with previously published Tenacibaculum genomes. We used Average Nucleotide Identity and core genome-based phylogeny as a proxy index for species boundary delineation. This work highlights evolution of closely related fish-pathogenic species and suggests that homologous recombination likely contributes to genome evolution. It also corrects the species affiliation of strain AYD7486TD claimed by Grothusen et al. (2016).
Veterinary Research
Tenacibaculum maritimum is responsible for tenacibaculosis, a devastating marine fish disease. This filamentous bacterium displays a very broad host range and a worldwide geographical distribution. We analyzed and compared the genomes of 25 T. maritimum strains, including 22 newly draft-sequenced genomes from isolates selected based on available MLST data, geographical origin and host fish. The genome size (~3.356 Mb in average) of all strains is very similar. The core genome is composed of 2116 protein-coding genes accounting for ~75% of the genes in each genome. These conserved regions harbor a moderate level of nucleotide diversity (~0.0071 bp−1) whose analysis reveals an important contribution of recombination (r/m ≥ 7) in the evolutionary process of this cohesive species that appears subdivided into several subgroups. Association trends between these subgroups and specific geographical origin or ecological niche remains to be clarified. We also evaluated the potential of MALDI-...
Advancements in Characterizing Tenacibaculum Infections in Canada
Pathogens, 2020
Tenacibaculum is a genus of gram negative, marine, filamentous bacteria, associated with the presence of disease (tenacibaculosis) at aquaculture sites worldwide; however, infections induced by this genus are poorly characterized. Documents regarding the genus Tenacibaculum and close relatives were compiled for a literature review, concentrating on ecology, identification, and impacts of potentially pathogenic species, with a focus on Atlantic salmon in Canada. Tenacibaculum species likely have a cosmopolitan distribution, but local distributions around aquaculture sites are unknown. Eight species of Tenacibaculum are currently believed to be related to numerous mortality events of fishes and few mortality events in bivalves. The clinical signs in fishes often include epidermal ulcers, atypical behaviors, and mortality. Clinical signs in bivalves often include gross ulcers and discoloration of tissues. The observed disease may differ based on the host, isolate, transmission route, a...
New salmonid hosts for Tenacibaculum species: Expansion of tenacibaculosis in Chilean aquaculture
Journal of Fish Diseases, 2020
The success and sustainability of Chilean aquaculture largely depends on the control of endemic and emerging pathogens, including several species of the genus Tenacibaculum. Tenacibaculum dicentrarchi and “Tenacibaculum finnmarkense” have been detected and confirmed in Chilean Atlantic salmon (Salmo salar). However, no outbreaks of tenacibaculosis in rainbow trout (Oncorhynchus mykiss) or coho salmon (Oncorhynchus kisutch) have been reported, either in Chile or globally. The aims of this study were to determine whether the mortalities recorded for rainbow trout and coho salmon from five marine fish farms located in the Los Lagos, Aysén, and Magallanes Regions could be caused by Tenacibaculum spp. The diseased fish exhibited cutaneous haemorrhages, tail and peduncle rots, and damage on the mouth and tongue. Microbiological analysis of infected external tissues yielded 13 bacterial isolates. The isolates were identified as members of the genus Tenacibaculum through biochemical analysi...
Canadian Journal of Fisheries and Aquatic Sciences
Juvenile sockeye salmon (Oncorhynchus nerka) in British Columbia migrate past numerous Atlantic salmon (Salmo salar) farms from which they may acquire infectious agents. We analyse patterns of molecular detection in juvenile sockeye for the bacterium Tenacibaculum maritimum, known to cause disease in fish globally and to cause mouthrot disease in farmed Atlantic salmon in British Columbia. Our data show a clear peak in T. maritimum detections in the Discovery Islands region of British Columbia, where sockeye migrate close to salmon farms. Using well-established differential equation models to describe sockeye migration and bacterial infection, fit to detection data, we assessed support for multiple hypotheses describing farm- and background-origin infection. Our best models (with 99.8% empirical support) describe constant background infection pressure, except around Discovery Islands salmon farms, where farm-origin infection pressure peaked at 12.7 (approximate 95% CI: 4.5 to 31) ti...
Tenacibaculum ovolyticum 16S rDNA Quantitative-PCR Assay Development and Field Testing
Fishes
In British Columbia (BC; Canada) Atlantic salmon (Salmo salar L.) production, Tenacibaculum members are associated with ‘mouthrot’ and disease identification is based on gross observation and clinical data. Genomic similarities (i.e., putative virulence factors) between T. ovolyticum and other better-characterized agents of mouthrot could imply potential pathogenicity. While T. ovolyticum has not been directly linked to salmon mortality events in BC, it has been isolated from diseased marine fish. To investigate T. ovolyticum’s pathogenicity in situ, a T. ovolyticum 16S rDNA qPCR assay targeting a ~155 bp amplicon was developed. The assay was used to screen 67 biotic and 33 abiotic samples collected from a BC Atlantic salmon (Salmo salar L.) net-pen site before, during, and after a mouthrot outbreak. The assay was specific, quantifiable and detectable for T. ovolyticum over 6-log and 8-log units, respectively. However, cycle quotients differed between the BC isolate and type strain ...
Pathogens, 2021
Tenacibaculum are frequently detected from fish with tenacibaculosis at aquaculture sites; however, information on the ecology of these bacteria is sparse. Quantitative-PCR assays were used to detect T. maritimum and T. dicentrarchi at commercial Atlantic salmon (Salmo salar) netpen sites throughout several tenacibaculosis outbreaks. T. dicentrarchi and T. maritimum were identified in live fish, dead fish, other organisms associated with netpens, water samples and on inanimate substrates, which indicates a ubiquitous distribution around stocked netpen sites. Before an outbreak, T. dicentrarchi was found throughout the environment and from fish, and T. maritimum was infrequently identified. During an outbreak, increases in the bacterial load in were recorded and no differences were recorded after an outbreak supporting the observed recrudescence of mouthrot. More bacteria were recorded in the summer months, with more mortality events and antibiotic treatments, indicating that seasona...
Journal of Applied Microbiology, 2004
The aim of the present study was to evaluate the intraspecific genetic variability within Tenacibaculum maritimum strains isolated from different species of marine fish. Methods and Results: Twenty-nine strains isolated from five different fish species and three reference strains were characterized by randomly amplified polymorphic DNA (RAPD) method. Cluster analysis of RAPD-PCR profiles showed that the strains, regardless of the oligonucleotide primer employed (P2 and P6), were separated into two main groups that strongly correlated with the host species and/or O-serotypes described for this pathogen. One group composed all strains isolated from sole (Solea senegalensis and S. solea) and gilthead seabream (Sparus aurata), and the other compiled the T. maritimum isolates from yellowtail (Seriola quinqueradiata), Atlantic salmon (Salmo salar) and turbot (Scophthalmus maximus). An important exception was observed in the RAPD patterns of the reference strains, which were included in different genetic groups depending on the primer employed.
Frontiers in Cellular and Infection Microbiology
Tenacibaculosis occurs due to the marine bacterial pathogen Tenacibaculum maritimum. This ulcerative disease causes high mortalities for various marine fish species worldwide. Several external clinical signs can arise, including mouth erosion, epidermal ulcers, fin necrosis, and tail rot. Research in the last 15 years has advanced knowledge on the traits and pathogenesis mechanisms of T. maritimum. Consequently, significant progress has been made in defining the complex host-pathogen relationship. Nevertheless, tenacibaculosis pathogenesis is not yet fully understood. Continued research is urgently needed, as demonstrated by recent reports on the re-emerging nature of tenacibaculosis in salmon farms globally. Current sanitary conditions compromise the development of effective alternatives to antibiotics, in addition to hindering potential preventive measures against tenacibaculosis. The present review compiles knowledge of T. maritimum reported after the 2006 review by Avendaño-Herr...