Overview
Vibrio rhodolitus is a Gram-negative marine bacterium first isolated from rhodoliths (coralline algae structures) in the Abrolhos Bank, Brazil. Unlike many Vibrio species that are known pathogens, V. rhodolitus has demonstrated beneficial probiotic properties in aquaculture settings. Research has shown this species to be non-pathogenic to fish and may actually enhance host health through antioxidant activity and antagonism against harmful bacteria. This makes V. rhodolitus a notable exception among Vibrio species and a promising candidate for beneficial applications in marine aquaculture.
Affected species (hosts)
V. rhodolitus is notably non-pathogenic based on current research:
- Hybrid grouper (Epinephelus fuscoguttatus × E. lanceolatus) – beneficial gut inhabitant with probiotic properties
- No evidence of pathogenicity in fish hosts – showed non-hemolytic activity
- No disease associations reported in corals or other marine invertebrates
Environmental Associations:
- Rhodoliths (coralline algae structures) – natural habitat where first discovered
- Marine sediments and water column in tropical reef environments
- Gut microbiome of healthy marine fish
Probiotic Properties and Beneficial Applications
Antioxidant Activity. V. rhodolitus isolate GO 91 has demonstrated strong antioxidant properties, which may help protect fish from oxidative stress in aquaculture environments. This antioxidant capacity could be particularly beneficial during periods of environmental stress or high stocking densities.
Antagonistic Effects: Research has shown that V. rhodolitus exhibits antagonism against known fish pathogens, suggesting it could serve as a biological control agent in aquaculture systems. This competitive exclusion mechanism may help prevent establishment of harmful bacteria in fish gut microbiomes.
Non-pathogenic Profile: Unlike many Vibrio species, V. rhodolitus showed no hemolytic activity and caused no disease symptoms in fish hosts. This safety profile, combined with its beneficial properties, makes it an attractive probiotic candidate for marine aquaculture applications.
Antibiotic Sensitivity: V. rhodolitus has shown sensitivity to common aquaculture antibiotics, which provides a safety margin for management in case intervention becomes necessary. This sensitivity pattern also suggests the species has not developed significant antibiotic resistance mechanisms.
Management and Prevention Strategies
Beneficial Applications. V. rhodolitus may be considered as a probiotic supplement in marine aquaculture systems to enhance fish health and disease resistance. Monitor fish health parameters when introducing any new bacterial strains.
Environmental Monitoring. While non-pathogenic, maintain standard water quality monitoring practices. V. rhodolitus appears to thrive in healthy marine environments with good water quality.
Identification Accuracy: Ensure proper species identification using molecular methods, as Vibrio species can be difficult to distinguish morphologically. Misidentification could lead to confusion with pathogenic Vibrio species.
Research Applications: V. rhodolitus represents an interesting model for studying beneficial Vibrio-host interactions and may provide insights into developing probiotic treatments for marine aquaculture.
Antibiotic Considerations: While V. rhodolitus is sensitive to antibiotics, focus should be on maintaining its beneficial properties rather than elimination. Standard biosecurity practices remain important even with beneficial bacteria.
V. rhodolitus in reef tanks
Prevalence
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
Comparing the levels of this pathogen in your tank with those found in other tanks provides a context for interpreting your test results.
References
Zhang, Q., et al. (2022). Screening and Characterization of Potential Antioxidant Probiotics Isolated from the Gut of Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Frontiers in Marine Science, 9, 933304. https://doi.org/10.3389/fmars.2022.933304
Silva, C., et al. (2018). Genome Sequences of Vibrio maerlii sp. nov. and Vibrio rhodolitus sp. nov., Isolated from Rhodoliths. Microbiology Resource Announcements, 7(18), e01039-18. https://doi.org/10.1128/mra.01039-18
Tanaka, M., et al. (2019). Vibrio taketomensis sp. nov. by genome taxonomy. Systematic and Applied Microbiology, 42(6), 126048. https://doi.org/10.1016/j.syapm.2019.126048