Clonal Dynamics, Virulence Genes, Antimicrobial Resistance, and Early Diagnostic Indicators of Bloodstream Infections of Vibrio vulnificus in a Hospital in Eastern China from 2021 to 2024.

Objective: This study analyzes the characteristics and clonal dynamics of Vibrio vulnificus isolated from a Chinese hospital between 2021 and 2024. Methods: We performed whole genome sequencing (WGS) on the six collected Vibrio vulnificus isolates. Antibiotic susceptibility testing was conducted using the bioMérieux automated antimicrobial susceptibility testing system. The clonal dynamics were studied through phylogenetic analysis, and the clinical diagnostic value indicators for bloodstream infections (BSI) were evaluated using the receiver operating characteristic (ROC) curve. Results: The six Vibrio vulnificus strains collected in this study were phylogenetically closely related, including two of sequence type ST678 and one each of ST696, ST675, ST607, and ST367. All strains tested positive for the vcgC gene; five were positive for 16S rRNA type A, and one showed type AB. Virulence gene profiling revealed that the strains universally carried exotoxins (VvhA, RTX), adhesion factors (TadZ/CpaE, IlpA, VWA), and motility-associated genes (cheW/R, motA, flgC). Notably, one strain harbored a broader array of virulence factors, including effector protein secretion systems (ompA, vipA/tssB, sciN/tssJ), biofilm formation-related genes (mrkA/B/C), and siderophores (fepA/B, entE/F, iucA/B), which may significantly enhance its pathogenicity. According to CLSI guidelines for Vibrio spp. all isolates were resistant to ampicillin but susceptible to third-generation cephalosporins, carbapenems, tetracyclines, quinolones, and folate pathway inhibitors. ROC curve analysis showed that high-sensitivity C-reactive protein (HS-CRP), lactate (Lac), procalcitonin (PCT), and other indicators were of good clinical value for the early diagnosis of bloodstream infection caused by Vibrio vulnificus. Conclusion: This study represents the inaugural whole-genome sequencing research conducted on Vibrio vulnificus isolates from eastern China. It comprehensively examines the current species, antibiotic resistance, virulence genes, and clinical characteristics of infected individuals, elucidating the pathogenic mechanisms and epidemiological features of Vibrio vulnificus. The findings offer essential references for clinical diagnosis and treatment.