Background: Vibrio vulnificus  (VV) is a causative agent of foodborne diseases with high mortality. The aim of this study was to investigate the genomic and phenotypic profiles of VV.
Methods: Six VV isolates were collected and conducted whole-genome sequencing. Biofilm formation and anti-complement killing test were performed to evaluate the pathogenicity. Subsequently, 157 publicly available genomes of VV isolates were selected to determine the evolutionary relationship.
Results: The resistant genes norM  and tet34  were identified in six isolates. A total of 156 virulence genes were identified. However, there is no obvious difference between strains isolated from blood and puncture fluid. The tendency of growth for six isolates decreased with the lapse of time, while the biofilm formation increased. The genes tadC  and flp  related to Flp pili were found in isolate 25506 and 30896, resulting in more obvious biofilm formation. In addition, the survival rate of 19656 was less than 20% due to lack of one genomic island including virulence genes (impD-H, clpV-1 ) relevant to type VI secretion system (T6SS). Multi-locus sequence typing (MLST) revealed 95 different STs and 19 novel STs, indicating that the tendency of 163 isolates was sporadic. Further comparative genomics analysis clearly classified 163 isolates into three distinct evolutionary lineages.
Conclusion: VV infections were sporadic in humans and the environment. Virulence genes impD-H  and clpV-1  related to T6SS were associated with pathogenicity phenotype of VV.
Keywords: resistance genes, virulent factors, biofilm, type VI secretion system