Pathogenic Bacteria in Aquatic Environments

Pathogenic bacteria occupy diverse aquatic habitats—from freshwater rivers and lakes to brackish estuaries and coastal seas—and pose multifaceted threats to human health, aquaculture productivity and ecosystem integrity. Common genera such as Aeromonas, Vibrio and Plesiomonas flourish under conditions of organic enrichment, temperature elevation and salinity fluctuation, exploiting opportunities to colonise fish, crustaceans and shellfish. Their pathogenic strategies include adhesion via specialised fimbriae, invasion mediated by secretion systems and toxin production that disrupts host tissues and immune defences. Many strains form resilient biofilms on biotic and abiotic surfaces, enhancing persistence and facilitating horizontal transfer of virulence factors and antibiotic-resistance genes. Intensification of aquaculture, global trade in live seafood and climate-driven warming of waters have expanded both the range and incidence of outbreaks. Advances in high-throughput sequencing, metagenomics and molecular serotyping are improving surveillance, while targeted interventions—such as probiotic supplements, vaccination and improved water management—are being deployed to mitigate disease emergence and safeguard food security.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Research from all publishers

Genomic and comparative analyses of Plesiomonas shigelloides recovered from diseased rainbow trout have identified extensive repertoires of antibiotic-resistance determinants, secretion systems and adhesion factors, leading to the proposition of a novel subspecies. Parallel studies in carp have isolated strains that cause widespread organ inflammation, bleeding and necrosis, with transcriptomic profiling of infected tissues revealing activation of TNF and IL-17 signalling pathways and Toll-like receptor cascades in the host. Bioinformatic profiling of publicly available P. shigelloides genomes has further delineated strain-specific pathogenicity islands and candidate virulence genes, underscoring the genetic heterogeneity of this emerging fish pathogen. In aquaculture settings, Aeromonas caviae isolates from goldfish have demonstrated multidrug resistance yet remain susceptible to yeast-derived glycoprotein antimicrobials, offering a promising alternative to conventional antibiotics. Environmental surveys of lake water and fish microbiota have uncovered persistent populations of Serratia fonticola and Aeromonas salmonicida with high levels of antibiotic resistance, highlighting the necessity of integrated water-quality management and molecular monitoring tools.

Pathogenic Bacteria in Aquatic Environments publication trend

The graph below shows the total number of articles in pathogenic bacteria in aquatic environments across all publications each year (not limited to Nature Index journals).

Technical terms

Biofilm: A structured consortium of microorganisms embedded in a self-produced polymeric matrix that adheres to surfaces and confers protection against environmental stresses.

Secretion system: A specialised molecular apparatus in Gram-negative bacteria used to transport effector proteins across cell membranes to manipulate host cells.

Metagenomics: The culture-independent study of collective microbial genomes within an environmental sample, enabling detection of both culturable and unculturable organisms.

Serotyping: The classification of bacteria into distinct groups based on variations in surface antigens, notably O-antigens of lipopolysaccharides, to support epidemiological tracking.

References

1. Description of a Novel Fish Pathogen, Plesiomonas shigelloides subsp. oncorhynchi, Isolated from Rainbow Trout (Oncorhynchus mykiss): First Genome Analysis and Comparative Genomics. Fishes (2023).
2. Isolation, Identification, and Investigation of Pathogenic Bacteria From Common Carp (Cyprinus carpio) Naturally Infected With Plesiomonas shigelloides. Frontiers in Immunology (2022).
3. Pathogenomics of Virulence Traits of Plesiomonas shigelloides That Were Deemed Inconclusive by Traditional Experimental Approaches. Frontiers in Microbiology (2018).
4. A potential alternative to traditional antibiotics in aquaculture: Yeast glycoprotein exhibits antimicrobial effect in vivo and in vitro on Aeromonas caviae isolated from Carassius auratus gibelio. Veterinary Medicine and Science (2020).
5. Bacterial Communities and Antibiotic Resistance of Potential Pathogens Involved in Food Safety and Public Health in Fish and Water of Lake Karla, Thessaly, Greece. Pathogens (2022).
6. O-Antigen Gene Clusters of Plesiomonas shigelloides Serogroups and Its Application in Development of a Molecular Serotyping Scheme. Frontiers in Microbiology (2019).