The Molecular Biological Characteristics of Vibrio vulnificus Isolated from Wenzhou, China

Vibrio vulnificus, a major human-pathogenic Vibrio species, causes foodborne or wound-related infections with a globally rising incidence. The study aimed to characterize the molecular characteristics of V. vulnificus to support the prevention, control, and clinical treatment of its infection. A total of 63 V. vulnificus isolates from seafood and patients in Wenzhou were subjected to sequencing, bioinformatic analysis, and antimicrobial susceptibility testing. Single nucleotide polymorphism and multilocus sequence typing analysis of 100 isolates (63 from this study, 37 from the NCBI database) were performed to assess genetic characteristics. Nine key virulence genes, associated with adhesion, RTX toxin, and T6SS, and eight antimicrobial resistant genes (ARGs) were identified. All isolates were resistant to colistin (CT), with 74.6%, 58.7%, and 3.2% resistance to streptomycin, amikacin, and nalidixic acid, respectively, and were susceptible to 12 other tested antimicrobials. V. vulnificus infection cases in this study showed a significant demographic skew toward males aged ≥50 years. The isolates exhibited genetic diversity while sharing virulence genes and ARGs. In silico detected ARGs could not accurately predict in vitro antimicrobial resistance phenotypes, so extreme caution is required when using ARGs detection results to guide clinical anti-infective medication. This study provides basic genomic and phenotypic data of local V. vulnificus isolates, which may serve as a reference for local surveillance and clinical empirical treatment of V. vulnificus infection.