Vibrio thalassae

Overview

Vibrio thalassae is a Gram-negative marine bacterium that was formally described as a distinct species separate from V. mediterranei and V. shilonii in 2014. This bacterium has been isolated from a diverse range of marine hosts including mussels, oysters, clams, coral, fish, and plankton across various geographic locations. While V. thalassae is commonly found in marine environments and associated with marine organisms, its role as a pathogen remains unclear, with no direct evidence currently linking it to disease outbreaks in fish, corals, or aquaculture settings.

Affected species (hosts)

Marine Hosts (Isolation Sources):

  • Mussels – source of original isolates
  • Oysters – found in various oyster species
  • Clams – detected in multiple clam species
  • Coral – isolated from coral tissues
  • Marine fish – present in fish samples
  • Plankton – found in planktonic communities

Current Status:

  • No confirmed pathogenic role established
  • No documented disease outbreaks attributed to V. thalassae
  • No association observed between strain grouping and host or geographic origin
  • Distinguished from closely related pathogenic species V. mediterranei and V. shilonii

Taxonomic Identity and Host Range

Species Description and Differentiation. Vibrio thalassae was formally described in 2014 through multilocus sequence analysis that distinguished it from previously confused species V. mediterranei and V. shilonii. This taxonomic clarification was crucial because these closely related species have different pathogenic potentials, with V. mediterranei being associated with mortality events in marine bivalves.

Broad Host Association: Unlike many Vibrio species that show host specificity, V. thalassae has been isolated from an unusually diverse range of marine organisms spanning multiple taxonomic groups. This broad association pattern suggests either a commensal lifestyle or opportunistic presence rather than specialized pathogenesis.

Geographic Distribution: Strains have been isolated from various geographic locations with no clear pattern linking genetic groupings to specific hosts or regions. This widespread distribution indicates V. thalassae is a cosmopolitan marine bacterium rather than a geographically restricted pathogen.

Pathogenic Potential Assessment: Current research has not established V. thalassae as a primary pathogen, contrasting with its close relative V. mediterranei which has been linked to mass mortality events in marine bivalves under stress conditions. The lack of disease association may indicate a more benign ecological role.

Management and Prevention Strategies

Prevention. Given the unclear pathogenic status of V. thalassae, focus on general marine biosecurity practices including quarantine of new specimens, regular health monitoring, and maintenance of optimal water quality parameters.

Monitoring Approach. Since V. thalassae pathogenicity is not established, routine screening may not be necessary unless part of broader bacterial monitoring programs. Focus surveillance efforts on confirmed pathogens like V. mediterranei and V. coralliilyticus.

Species Identification: Accurate identification using molecular methods is important to distinguish V. thalassae from related pathogenic species. Misidentification could lead to unnecessary treatment or missing actual pathogenic species.

Environmental Management: Maintain stable environmental conditions to prevent stress that might predispose organisms to opportunistic infections. Monitor closely related species V. mediterranei which can cause mortality under stress conditions.

Research Gaps: Current knowledge is limited regarding V. thalassae pathogenic potential. Future research may clarify its ecological role and any disease associations, particularly under stress conditions or in specific host-pathogen combinations.

V. thalassae in reef tanks

Prevalence

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Looking at how common this pathogen is in other tanks can help you gauge whether finding it in your tank is expected or unusual.

Abundance Distribution

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Comparing the levels of this pathogen in your tank with those found in other tanks provides a context for interpreting your test results.

References

Tarazona, E., Lucena, T., Arahal, D. R., Macián, M., Ruvira, M. A., & Pujalte, M. P. (2014). Multilocus sequence analysis of putative Vibrio mediterranei strains and description of Vibrio thalassae sp. nov. Systematic and Applied Microbiology, 37(5), 350-357. https://doi.org/10.1016/j.syapm.2014.05.005

Torres, M. E., Reina, J. C., Fuentes-Monteverde, J. C., Fernández, G., Rodríguez, J., Jiménez, C., & Llamas, I. (2018). AHL-lactonase expression in three marine emerging pathogenic Vibrio spp. reduces virulence and mortality in brine shrimp (Artemia salina) and Manila clam (Venerupis philippinarum). PLoS ONE, 13(4), e0195176. https://doi.org/10.1371/journal.pone.0195176

Prado, P., Carrasco, N., Catanese, G., Grau, A., Cabanes, P., Carella, F., García-March, J. R., Tena, J., Valdés Roque, A. I., Bertomeu, E., Gras, N., Caiola, N., Furones, M. D., & Andree, K. (2020). Presence of Vibrio mediterranei associated to major mortality in stabled individuals of Pinna nobilis L. Aquaculture, 520, 734950. https://doi.org/10.1016/j.aquaculture.2019.734899

Zhao, Z., Omae, K., Iwasaki, W., Zhang, Z., Pan, F., Lee, E.-J., & Hattori, M. (2025). Bioinformatics classification of the MgtE Mg²⁺ channel and de novo protein design for the stabilization of its novel subclass. bioRxiv. https://doi.org/10.1101/2025.05.26.656215