Molecular Epidemiology, Antibiotic Susceptibility, and Virulence Profiling of <i>Vibrio parahaemolyticus</i> Isolated from Aquatic Foods in Shenzhen, China

Vibrio parahaemolyticus is a common food-borne pathogen associated with aquatic foods, posing a major threat to human health worldwide. In this study, 22 isolates from aquatic foods were collected from 70 samples in Shenzhen, Guangdong, China (2023–2025). All isolates were subjected to antibiotic susceptibility testing, serotyping, and screening for antibiotic resistance genes and virulence factors. The results indicated that the most prevalent serotypes were O1 (45.4%), O14 (18.2%), while K -type exhibited greater genetic diversity. Multilocus sequence typing analysis divided the 22 isolates into 10 sequence types (STs), and the predominant ST was ST1823 (18.2%). Antimicrobial susceptibility tests showed that 18.2% of isolates (VP363, VP412, VP442, and VP452) were resistant to over five antibiotics. High resistance was observed to ampicillin (100%) and cefazolin (81.82%). A total of 15 antimicrobial resistance genes were identified. Among them, the tet(A) gene was detected in all isolates, while the blaCARB gene was found in the majority of isolates. Notably, the virulence genes tdh and trh were both absent in all strains. In addition, nearly all V. parahaemolyticus isolates in this study were found to harbor genes encoding the type III secretion system. These findings contribute to a better understanding of the characteristics of V. parahaemolyticus from aquatic products and provide fundamental data for ensuring food safety via the control of V. parahaemolyticus contamination.