Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA


Luxin Wang*, Zhuosheng Liu, Chao Liao

 Department of Food Science and Technology

University of California Davis, Davis, CA 95616


Vibrio parahaemolyticus (Vp) is an important foodborne pathogen worldwide and has been one leading cause of seafood-associated human gastroenteritis in the United States. However, knowledge gap still exists about the fitness and survival mechanisms of Vp in pre-harvest environment.

Two pathogenic ATCC strains of VP43996 (tdh+) and VP17802 (trh+) were used as the model organisms. Overnight fresh and washed cultures were inoculated into autoclaved natural seawater and stored at 10 °C for 10 days and 30 °C for 5 days (representing the average seawater temperatures in winter and summer months). The surviving Vp was determined by plating inoculated seawater onto thiosulfate-citrate-bile salts-sucrose agar (TCBS). Total RNA was extracted from the artifically-inoculated seawater 2 hours after inoculation and on Day 5 for samples stored at 10 and 30 °C by using the Qiagen RNAeasy mini kits. cDNA library was prepared by using the Qiagen QuantiTect Reverse Transcription Kit and sequenced with the Illumina Hiseq platform to produce 2 x 50 bp pair end short reads. Transcriptomics analysis was conducted to profile the transcriptome of Vp at different harvesting water temperatures.

The survival of Vp in artificially-inoculated seawater at two storage temperatures are illustrated in Figure 1. At 10 °C, the trh+ strain survived with greater numbers than the tdh+ strain. At 30 °C, the viable counts of both Vp strains reached plateau after 24 hours and remained at ~6.8 Log CFU/ml for the rest of the storage time. Compared with the strains stored at 30 °C, the Gene Set Enrichment Analysis based on the Kyoto Encyclopedia of Genes and Genomes (GSEA-KEGG) in Figure 2 provides biological insights of Vp persisted in seawater at 10 °C. It was found that both the histidine metabolism and biofilm formation metabolism pathways were significantly downregulated for both Vp strains at 10 °C.