Search Results (7)

Vibrio parahaemolyticus is a major foodborne pathogen worldwide, responsible for seafood-associated poisoning. Among its toxin genes, tdh2 is the most critical. To investigate the role of tdh2 in V. parahaemolyticus under gastrointestinal conditions, we constructed tdh2 deletion and complementation strains and compared their survival under acid (pH 3 and 4) and bile stress (2%). The results showed that tdh2 expression was significantly upregulated under cold (4 °C) and bile stress (0.9%). Survival assays and PI staining revealed that the tdh2 mutant strain (VP: △tdh2) was more sensitive to acid and bile stress than the wild-type (WT), and this sensitivity was rescued by tdh2 complementation. These findings suggest that tdh2 plays a protective role in enhancing V. parahaemolyticus tolerance to acid and bile stress. In the VP: △tdh2 strain, seven genes were significantly upregulated and six were downregulated as a result of tdh2 deletion. These genes included VPA1332 (vtrA), VPA1348 (vtrB), VP2467 (ompU), VP0301 and VP1995 (ABC transporters), VP0527 (nhaR), and VP2553 (rpoS), among others. Additionally, LC-MS/MS analysis identified 12 differential metabolites between the WT and VP: △tdh2 strains, including phosphatidylserine (PS) (17:2 (9Z,12Z) /0:0 and 20:1 (11Z) /0:0), phosphatidylglycerol (PG) (17:0/0:0), flavin mononucleotide (FMN), and various nucleotides. The protective mechanism of tdh2 may involve preserving cell membrane permeability through regulation of ompU and ABC transporters and enhancing electron transfer efficiency via regulation of nhaR. The resulting reduction in ATP, DNA, and RNA synthesis—along with changes in membrane permeability and electron transfer due to decreased FMN—likely contributed to the reduced survival of the VP: △tdh2 strain. Meanwhile, the cells actively synthesized phospholipids to repair membrane damage, leading to increased levels of PS and PG. This study provides important insights into strategies for preventing and controlling food poisoning caused by tdh⁺ V. parahaemolyticus. Full article

Vibrio parahaemolyticus is the leading cause of bacterial diarrhea in humans from shellfish consumption. In Thailand, blood clam is a popular shellfish, but homemade cooking often results in insufficient heating. Therefore, consumers may suffer from food poisoning due to Vibrio infection. This study aimed to determine the effect of chitooligosaccharide conjugated with epigallocatechin gallate (COS-EGCG) at different concentrations (200 and 400 ppm) combined with high-voltage atmospheric cold plasma (HVACP) on inhibiting V. parahaemolyticus in vitro and in challenged blood clam meat. Firstly, HVACP conditions were optimized for gas composition and treatment time (20 and 60 s); a 70% Ar and 30% O₂ gas mixture resulted in the highest ozone formation and a treatment time of 60 s was used for further study. COS-EGCG conjugate at 400 ppm with HVACP (ACP-CE400) completely killed V. parahaemolyticus after incubation at 37 °C for 6 h. Furthermore, an antibacterial ability of ACP-CE400 treatment against bacterial cells was advocated due to the increased cell membrane damage, permeability, and leakage of proteins and nucleic acids. Scanning electron microscopy (SEM) showed cell elongation and pore formation, while confocal microscopy revealed disrupted biofilm formation. Additionally, the shelf life of challenged blood clam meat treated with ACP-CE400 was extended to nine days. SEM analysis revealed damaged bacterial cells on the meat surface after ACP-CE400 treatment, indicating the antibacterial activity of the combined treatment. Thus, HVACP combined with COS-EGCG conjugate, especially at a highest concentration (400 ppm), effectively inhibited microbial growth and extended the shelf life of contaminated blood clam meat. Full article

Background/Objectives: Vibrio parahaemolyticus is a marine bacterium and a major cause of food poisoning worldwide, primarily associated with gastric illnesses such as gastroenteritis. This study aimed to investigate the distribution, antibiotic resistance, and virulence genes of V. parahaemolyticus present in shellfish and seawater of the southern coast of Korea, a major shellfish harvesting area. Methods: Shellfish and seawater samples were collected monthly in 2023 from 24 coastal sites in Korea. V. parahaemolyticus was isolated and identified using the MPN method, biochemical tests, MALDI-TOF mass spectrometry, and 16S rRNA sequencing. Antimicrobial susceptibility was tested for 673 isolates using the Sensititre MIC system, and virulence genes (tdh and trh) were detected by PCR. Results:V. parahaemolyticus had a detection rate of 18.2–58.3% in shellfish and 8.3–50% in seawater samples. Among the isolates, 97.9% and 97.3% were resistant to ampicillin and colistin, respectively, while 8.3% showed resistance to four or more antibiotics. The virulence genes tdh and trh were detected in 0.45% and 3.34% of shellfish samples and 1.23% and 4.46% of seawater samples, respectively. Conclusions: These findings will help implement appropriate precautionary measures to prevent potential human health risks arising from exposure to multidrug-resistant or pathogenic V. parahaemolyticus. Full article

Vibrio parahaemolyticus is a ubiquitous inhabitant of estuarine and marine environments that causes vibriosis in aquatic animals and food poisoning in humans. Accessory colonizing factor (ACF) is employed by Vibrio to assist in the colonization and invasion of host cells leading to subsequent illnesses. In this work, ΔacfA, an in-frame deletion mutant strain lacking the 4th to the 645th nucleotides of the open reading frame (ORF) of the acfA gene, and the complementary strain acfA⁺ were constructed to decipher the function of AcfA in V. parahaemolyticus. The deletion of acfA had no effect on bacterial growth but resulted in a significant reduction in biofilm formation, hemolytic activity, mucus adhesion, and the accumulated mortality of zebrafish, compared to the wild-type strain and the complementary strain acfA⁺. Additionally, AcfA was involved in adapting to stressors, such as H₂O₂, EDTA, and acid, in V. parahaemolyticus. Furthermore, RNA-Seq transcriptome analysis was conducted to identify global gene transcription alterations resulting from deletion of the acfA gene. A total of 416 differentially expressed genes were identified in the ΔacfA vs. wild-type comparison, with 238 up-regulated genes and 178 down-regulated genes. The expression of genes associated with the type III secretion system, type VI secretion system, and oligopeptide permeases system were significantly reduced, and yet the expression of genes associated with cell envelope biosynthesis and response regulation system were enhanced dramatically in the absence of the acfA gene compared to the wild-type strain. These findings suggest that AcfA may play a role in the overall success of pathogenesis and the cell envelope stress response of V. parahaemolyticus. Full article

This study aimed to investigate the outbreaks and characteristics of Vibrio parahaemolyticus food poisoning in the Republic of Korea and the impact of climatic factors on the food poisoning occurrence. All data were obtained from the official statistics of the Republic of Korea (2002 to 2017). A trend analysis, Pearson’s correlation analysis, and regression analysis were used to determine the relationship between the outbreaks of V. parahaemolyticus food poisoning and climatic factors. During the study period, the number of outbreaks of V. parahaemolyticus food poisoning ranked third among bacterial food poisoning. The food poisoning incidences of V. parahaemolyticus occurred mostly from July to September. The average temperature, maximum and minimum temperatures, precipitation, number of days with rainfall, and humidity showed a significant positive correlation with the number of outbreaks of V. parahaemolyticus food poisoning (p < 0.001), but daytime hours showed a negative correlation (p < 0.01). The data further indicated that minimum temperature was the most influential variable on the outbreaks of food poisoning (p < 0.01). These results indicate that the outbreaks of V. parahaemolyticus food poisoning in the Republic of Korea are associated with climatic factors, suggesting that these incidences may have been impacted by climate change, especially due to warming around the Korean peninsula. Full article

Histamine is a toxic biogenic amine commonly found in seafood products or their derivatives. This metabolite is produced by histamine-producing bacteria (HPB) such as Proteus vulgaris, P. mirabilis, Enterobacter aerogenes, E. cloacae, Serratia fonticola, S. liquefaciens, Citrobacter freundii, C. braakii, Clostridium spp., Raoultella planticola, R. ornithinolytica, Vibrio alginolyticus, V. parahaemolyticus, V. olivaceus, Acinetobacter lowffi, Plesiomonas shigelloides, Pseudomonas putida, P. fluorescens, Aeromonas spp., Photobacterium damselae, P. phosphoreum, P. leiognathi, P. iliopiscarium, P. kishitanii, and P. aquimaris. In this review, the role of these bacteria in histamine production in fish and seafood products with consequences for human food poisoning following consumption are discussed. In addition, methods to control their activity in countering histamine production are proposed. Full article

This study aimed to investigate and quantify the relationship between climate variation and incidence of Vibrio parahaemolyticus in Taiwan. Specifically, seasonal autoregressive integrated moving average (ARIMA) models (including autoregression, seasonality, and a lag-time effect) were employed to predict the role of climatic factors (including temperature, rainfall, relative humidity, ocean temperature and ocean salinity) on the incidence of V. parahaemolyticus in Taiwan between 2000 and 2011. The results indicated that average temperature (+), ocean temperature (+), ocean salinity of 6 months ago (+), maximum daily rainfall (current (−) and one month ago (−)), and average relative humidity (current and 9 months ago (−)) had significant impacts on the incidence of V. parahaemolyticus. Our findings offer a novel view of the quantitative relationship between climate change and food poisoning by V. parahaemolyticus in Taiwan. An early warning system based on climate change information for the disease control management is required in future. Full article