Potential Risk Identification of Vibrio parahaemolyticus in Litopenaeus vannamei Aquaculture Farms

Abstract:

The prevalence, genetic diversity, and potential virulence of Vibrio parahaemolyticus were analyzed in Pacific whiteleg shrimp (Litopenaeus vannamei) aquaculture systems. In 2024, 354 samples were collected from L. vannamei aquaculture farms in Jiangmen and Zhongshan cities, Guangdong Province. The prevalence of V. parahaemolyticus was 41.53% (147/354). Six serogroups were identified via multiplex polymerase chain reaction (PCR), including O1, O3/O13, O5, O7, O11, and O12 serogroup. O1 (44.21%, 65/147) and O11 (31.97%, 47/147) were the dominant strains. PCR analysis showed that the presence of both tlh and toxR genes were 100%, whereas pirAB was detected in 24.49% (36/147) isolates; tdh and trh gene was not detected. A total of 26 different sequence types (STs) were identified using multilocus sequence typing, seven (26.92%) STs were identified as novel STs. ST2408 (17.69%, 26/147) was identified as the predominant ST. The antibiotic resistance of isolates was tested using minimum inhibitory concentration. Results showed that the resistance rate to polymyxin B was 11.56% (17/147), whereas the susceptibility to the other 21 antibiotics were all above 90%. A high prevalence of pirAB-carrying and polymyxin B-resistant V. parahaemolyticus isolates was identified in aquaculture farms, indicating a potential food safety risk. These results of this study provide fundamental data for the risk identification and molecular traceability of V. parahaemolyticus, which play an important role in healthy aquaculture practices and the prevention of potential risk of this pathogen.