“Impact and population dynamics in a German biofloc aquaculture: ‚What happens in an aquaculture stays in an aquaculture‘? (7039)”

Impact and population dynamics in a German biofloc aquaculture: ‚What happens in an aquaculture stays in an aquaculture‘?

Introduction: The genus Vibrio has the potential to exert a considerable influence on the field of aquaculture. While some species are classified as pathogenic to fish and seafood (e.g., V. campbellii/V. harveyi complex), other species, including V. vulnificus, V. cholerae and V. parahaemolyticus, have the potential to cause intestinal and extraintestinal infections in humans. In order to mitigate the risk of public health threats posed by aquaculture products, it is essential to gain a deeper understanding of the prevalence and impact of potentially human pathogenic Vibrio species. Methodology: The isolates were characterized by phenotypic and genotypic methods incl. antimicrobial susceptibility testing and biotyping. WGS sequencing and bioinformatics analysis was conducted to determine the population structure and to assess the impact of the isolates regarding virulence potential and transmissible resistance determinants. Results: As part of a qualitative Vibrio spp. monitoring of a German biofloc aquaculture in 2022, the occurrence and diversity of V. parahaemolyticus in shrimps and water samples over a period of one year were determined by conventional typing and SfiI-macrorestriction profiling, respectively. A further investigation was conducted 16 months after the last monitoring sampling in order to provide a comparison. In total, 214 strains of V. parahaemolyticus, originating from twelve shrimp and two water samples from one aquaculture basin, were investigated. Overall, the strains exhibited minimal variability in their SfiI-PFGE profiles across all sampling approaches, with 22 subclade clusters assigned to one clone, indicating the persistence of the predominant clonal type. In addition, antimicrobial susceptibility testing (AST), plasmid characterisation and whole-genome sequencing (WGS) was conducted to characterized the strain diversity in-depth. The observed differences between strains were mainly attributed to the presence of plasmids, which were identified in some of the strains. Conclusion: The study provides an overview about Vibrio spp. occurrence and insight into the impact of V. parahaemolyticus on human health and the persistence of a predominant clone.

1. HAMMERL, JENS ANDRE, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Presenter
2. BARON, SANDRINE, ANSES, Author
3. LeDevendec, Laetitia, ANSES, Author
4. Goellner, Cornelia, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
5. Nekat, Jonas, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
6. Manta, Diana, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
7. JAECKEL, CLAUDIA, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author