Vibrio alginolyticus

  • Coral and fish pathogen

Overview

Vibrio alginolyticus is a Gram-negative halophilic marine bacterium that serves as both an opportunistic pathogen and beneficial symbiont in marine environments. This versatile species is commonly found in seawater, marine sediments, and associated with various marine organisms including fish, corals, invertebrates, and shellfish. While it can cause vibriosis in aquaculture settings and has been implicated in coral diseases, V. alginolyticus also demonstrates beneficial properties, making it a complex organism of significant interest to saltwater aquarium hobbyists.

Affected species (hosts)

Fish:

  • Gilthead seabream (Sparus aurata)
  • Zebrafish (used in pathogenicity studies)
  • Various farmed marine fish species
  • Stingrays (Himantura uarnak and H. fai in aquarium settings)

Corals and Invertebrates:

  • Stony corals (various species in seawater aquaria)
  • Porites andrewsi (white syndrome)
  • Soft corals (as epibionts)
  • Shellfish and their larvae
  • Shrimp and other crustaceans

Other Marine Life:

  • Seaweed (can both cause and prevent bleaching disease)
  • Various marine invertebrates in aquaculture

How Does V. alginolyticus Cause Disease?

Virulence Factor Diversity: V. alginolyticus employs multiple virulence mechanisms including hemolysin production, biofilm formation, and specialized secretion systems. The outer membrane protein A (OmpA) serves as a key virulence factor affecting bacterial motility, biofilm formation, and overall pathogenicity in fish hosts.

Type III Secretion System: The bacterium utilizes a sophisticated Type III secretion system to inject toxins directly into host cells, inducing rapid apoptosis, cell rounding, and osmotic lysis in fish cells. This system allows for efficient delivery of virulence factors that disrupt normal cellular functions.

Quorum Sensing Regulation: V. alginolyticus uses complex quorum sensing systems regulated by LuxR-type proteins to coordinate virulence gene expression. These systems are temperature-dependent and allow the bacterium to sense population density and environmental conditions before mounting pathogenic attacks.

Environmental Adaptation: The bacterium shows remarkable adaptability to varying environmental conditions, with seasonal fluctuations and water quality parameters significantly influencing its virulence potential. Temperature changes particularly affect its pathogenic behavior in aquaculture settings.

Antibiotic Resistance: Many strains demonstrate complex patterns of antibiotic resistance, including intermediate resistance to multiple drug classes. The genetic similarity to other pathogenic Vibrio species like V. parahaemolyticus contributes to shared resistance mechanisms and complicates treatment approaches.

Management and Prevention Strategies

Prevention. Quarantine new fish and corals for 2-4 weeks minimum, with separate filtration for quarantine systems.  

Testing. Test new arrivals in the QT to make sure they’re pathogen-free before introducing them to your display. 

Beware of antibiotic resistance: Antibiotic resistance is widespread in this group. Avoid antibiotic treatments if at all possible.   

If you must use antibiotics: Most Vibrio species are susceptible to Ciprofloxacin and Oxalinic Acid.

But first see this note about the use of antibiotics in aquariums! 

V. alginolyticus in reef tanks

Prevalence

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Considering the prevalence of this pathogen 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

Hörmansdorfer, S., et al. (2000). Isolation of Vibrio alginolyticus from seawater aquaria. International Journal of Hygiene and Environmental Health, 203(2), 169-175. https://doi.org/10.1078/s1438-4639(04)70024-3

Xie, Z., et al. (2013). First characterization of bacterial pathogen, Vibrio alginolyticus, for Porites andrewsi white syndrome in the South China Sea. PLoS ONE, 8(9), e75425. https://doi.org/10.1371/journal.pone.0075425

Bunpa, S., et al. (2019). Outer membrane protein A (OmpA) is a potential virulence factor of Vibrio alginolyticus strains isolated from diseased fish. Journal of Fish Diseases, 42(12), 1693-1702. https://doi.org/10.1111/jfd.13120

Emam, A., et al. (2019). An outbreak of Vibrio alginolyticus infection in aquarium-maintained stingrays. The Egyptian Journal of Aquatic Research, 45(2), 149-155. https://doi.org/10.1016/j.ejar.2019.05.003

Liu, H., et al. (2020). Antimicrobial activity and virulence attenuation of citral against the fish pathogen Vibrio alginolyticus. Aquaculture, 515, 734578. https://doi.org/10.1016/j.aquaculture.2019.734578

Zhang, Y., et al. (2022). Transposon insertion sequencing analysis unveils novel genes involved in luxR expression and quorum sensing regulation in Vibrio alginolyticus. Microbiological Research, 267, 127243. https://doi.org/10.1016/j.micres.2022.127243

Yu, Y., et al. (2022). Antibiotic resistance, virulence and genetic characteristics of Vibrio alginolyticus isolates from aquatic environment in coastal mariculture areas in China. Marine Pollution Bulletin, 185(A), 114219. https://doi.org/10.1016/j.marpolbul.2022.114219

Aly, S., et al. (2023). Comprehensive analysis of Vibrio alginolyticus: Environmental risk factors in the cultured Gilthead seabream under seasonal fluctuations. Journal of Fish Diseases, 46(11), 1183-1195. https://doi.org/10.1111/jfd.13860

Ma, M., et al. (2023). Naturally occurring beneficial bacteria Vibrio alginolyticus X-2 protects seaweed from bleaching disease. mBio, 14(2), e00065-23. https://doi.org/10.1128/mbio.00065-23

Yu, Z., et al. (2024). Antibacterial effect of fermented pomegranate peel polyphenols on Vibrio alginolyticus and its mechanism. Biology, 13(11), 934. https://doi.org/10.3390/biology13110934

Minimol, A., et al. (2024). Molecular characteristics demonstrate the occurrence of phylogenetic similar isolates of Vibrio alginolyticus and Vibrio parahaemolyticus in aquatic environments. Fishery Technology, 61(4), 400-408. https://doi.org/10.56093/ft.v61i4.153421

Kalatzis, P., et al. (2016). Isolation and characterization of two lytic bacteriophages for biological control of Vibrio alginolyticus in aquaculture live feeds. PLoS ONE, 11(3), e0151101. https://doi.org/10.1371/journal.pone.0151101