Search Results (220)

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

The illegal sale of mussels is a persistent problem for food safety and public health in the Campania region, where bivalve molluscs are often sold without traceability, evading regulatory controls. In this study, ten batches of mussels seized from unauthorized vendors were analyzed to evaluate their microbiological safety and trace their geographical origin. High loads of Escherichia coli, exceeding European regulatory limits (Regulation (EC) No 2073/2005), were detected in all samples. In addition, Salmonella Infantis strains resistant to trimethoprim-sulfamethoxazole and azithromycin were isolated, raising further concerns about antimicrobial resistance. Of the 93 Vibrio isolates, identified as V. alginolyticus and V. parahaemolyticus, 37.63% showed multidrug resistance. Approximately 68.57% of the isolates were resistant to tetracyclines and cephalosporins. The presence of resistance to last-resort antibiotics such as carbapenems (11.43%) is particularly alarming. Near-infrared spectroscopy, combined with chemometric models, was used to obtain traceability information, attributing a presumed origin to the seized mussel samples. Of the ten samples, seven were attributed to the Phlegraean area. These findings have provided valuable insights, reinforcing the need for continuous and rigorous surveillance and the integration of innovative tools to ensure seafood safety and support One Health approaches. Full article

Vibrio parahaemolyticus (V. parahaemolyticus) is a preeminent seafood-borne pathogen, imposing significant economic burdens on global aquaculture. The escalating prevalence of multidrug-resistant strains has accentuated the critical urgency for developing sustainable biocontrol strategies. In this study, a bacteriophage designated vB_VPAP_XY75 (XY75) was isolated and biologically characterized to establish an effective control against V. parahaemolyticus. XY75 exhibited remarkable specificity toward V. parahaemolyticus, effectively lysing 46.2% of the target strains while showing no lytic activity against non-target bacterial species. Morphological characterization confirmed its taxonomic assignment to the Myoviridae family, featuring an icosahedral head (40 ± 2 nm) and contractile tail (60 ± 2 nm). XY75 demonstrated strong environmental tolerance, remaining stable at pH 4–11 and temperatures as high as 50 °C. At an optimal multiplicity of infection (MOI = 0.01), XY75 achieved a peak titer of 8.1 × 10¹⁰ PFU/mL, a 5 min latent period, and burst size of 118 PFU/cell. Critically, XY75 reduced V. parahaemolyticus in salmon by more than 5.98 log CFU/g (99.9%) within 6 h at 4 °C, demonstrating exceptional cold tolerance and lytic activity. Genomic analysis confirmed that no virulence or antibiotic resistance genes were present. These results establish XY75 as a safe and efficacious biocontrol candidate for seafood preservation, with particular utility under refrigerated storage conditions. 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

Vibrio parahaemolyticus is a pathogenic bacterium widely distributed in marine environments, posing significant threats to aquatic organisms and human health. The overuse and misuse of antibiotics has led to the development of multidrug- and pan-resistant V. parahaemolyticus strains. There is an urgent need for novel antibacterial therapies with innovative mechanisms of action. In this work, a genome-scale metabolic network model (GMSN) of V. parahaemolyticus, named VPA2061, was reconstructed to predict the metabolites that can be explored as potential drug targets for eliminating V. parahaemolyticus infections. The model comprises 2061 reactions and 1812 metabolites. Through essential metabolite analysis and pathogen–host association screening with VPA2061, 10 essential metabolites critical for the survival of V. parahaemolyticus were identified, which may serve as key candidates for developing new antimicrobial strategies. Additionally, 39 structural analogs were found for these essential metabolites. The molecular docking analysis of the essential metabolites and structural analogs further investigated the potential value of these metabolites for drug design. The GSMN reconstructed in this work provides a new tool for understanding the pathogenic mechanisms of V. parahaemolyticus. Furthermore, the analysis results regarding the essential metabolites hold profound implications for the development of novel antibacterial therapies for V. parahaemolyticus-related disease. Full article

Vibrio parahaemolyticus is the leading bacterial cause of gastroenteritis associated with aquatic food consumption globally. This study aimed to determine the prevalence of V. parahaemolyticus in aquatic foods from Huzhou and to identify the serotypes, antimicrobial resistance, virulence factors, and genetic relatedness of the strains. A total of 306 isolates were detected from 1314 aquatic food samples from 2022 to 2024. The results indicated that the most prevalent serotypes were O1:KUT (17.0%), O2:K28 (13.7%), and O2:KUT (13.1%). Multilocus sequence typing analysis divided the 306 isolates into 175 sequence types (STs), and the predominant sequence type was ST864 (3.3%). Antimicrobial susceptibility tests showed that 2.6% of isolates were multidrug resistant. High resistance was observed to ampicillin (64.7%) and streptomycin (44.4%). A total of seven antimicrobial categories of resistance genes were identified, and the resistance gene bla_CARB was detected in all isolates. The virulence genes tdh and trh were found in 16 (5.2%) and 12 (3.9%) isolates, respectively. In addition, we observed that all the 306 V. parahaemolyticus isolates encode type III secretion systems 1. The phylogenomic analysis based on the whole-genome sequence revealed that the 306 isolates were divided into four clusters. Our findings broaden perspectives on V. parahaemolyticus genetic diversity and enhance our ability to assess the potential risks of its spread. Full article

This study aimed to investigate the prevalence, antimicrobial resistance (AMR), and virulence characteristics of Vibrio parahaemolyticus (V. parahaemolyticus) isolated from olive flounder (Paralichthys olivaceus) and rockfish (Sebastes schlegelii) sashimi samples sold in South Korea from 2021 to 2022. A total of 500 fish samples were analyzed, from which 17 V. parahaemolyticus isolates were obtained. Antibiotic susceptibility testing using the minimum inhibitory concentration method revealed that 58.8% (10/17) of the isolates exhibited resistance to ampicillin, indicating the potential for AMR transmission in seafood-associated pathogens. Whole-genome sequencing (WGS) and a polymerase chain reaction detected the presence of tlh and trh virulence genes in all isolates, suggesting their pathogenic potential. Although the overall isolation rate of V. parahaemolyticus was low, the presence of virulence and AMR genes indicates public health relevance associated with raw seafood consumption. The increasing consumer demand for raw fish, coupled with environmental changes such as rising ocean temperatures, underscores the necessity of continuous surveillance to prevent foodborne outbreaks. These findings emphasize the need for targeted AMR monitoring and further research to mitigate the dissemination of resistant V. parahaemolyticus strains and enhance seafood safety. Full article

Vibrio species are among the primary pathogenic bacteria affecting abalone aquaculture, posing significant threats to farming practices. Current clinical control predominantly relies on antibiotics, which can result in antibiotic residues in both abalone and the surrounding marine environments. Lactobacillus plantarum (LP) has been shown to release bioactive antagonistic substances and exhibits potent inhibitory effects against marine pathogenic bacteria. This study aimed to screen and characterize the probiotic properties of LP strains isolated from rice wine lees to develop a novel biocontrol strategy against Vibriosis in abalone. The methods employed included selective media cultivation, streak plate isolation, and single-colony purification for strain screening, followed by Gram staining, 16S rDNA sequencing, and phylogenetic tree construction using MEGA11 for identification. The resilience, antimicrobial activity, and in vivo antagonistic efficacy of the strains were evaluated through stress tolerance assays, agar diffusion tests, and animal experiments. The results demonstrated the successful isolation and purification of four LP strains (NDMJ-1 to NDMJ-4). Phylogenetic analysis revealed closer genetic relationships between NDMJ-3 and NDMJ-4, while NDMJ-1 and NDMJ-2 were found to be more distantly related. All strains exhibited γ-hemolytic activity, bile salt tolerance (0.3–3.0%), and resistance to both acid (pH 2.5) and alkali (pH 8.5), although they were temperature sensitive (inactivated above 45 °C). The strains showed susceptibility to most of the 20 tested antibiotics, with marked variations in hydrophobicity (1.91–93.15%) and auto-aggregation (13.29–60.63%). In vitro antibacterial assays revealed that cell-free supernatants of the strains significantly inhibited Vibrio parahaemolyticus, V. alginolyticus, and V. natriegens, with NDMJ-4 displaying the strongest inhibitory activity. In vivo experiments confirmed that NDMJ-4 significantly reduced mortality in abalone infected with V. parahaemolyticus. In conclusion, the LP strains isolated from rice wine lees (NDMJ-1 to NDMJ-4) possess robust stress resistance, adhesion capabilities, and broad antibiotic susceptibility. Their metabolites exhibit significant inhibition against abalone-pathogenic Vibrios, particularly NDMJ-4, which demonstrates exceptional potential as a candidate strain for developing eco-friendly biocontrol agents against Vibriosis in abalone aquaculture. Full article

Traditional hazard identification techniques for Vibrio parahaemolyticus often neglect the distinction between viable and nonviable bacteria in aquatic products, leading to overestimated disease risks and uncertainties in risk assessments. To address this limitation, we developed an automated PMA pretreatment instrument that integrates dark incubation and photo-crosslinking into a unified workflow, allowing customizable parameters such as incubation time, light exposure duration, and mixing speed while maintaining stable temperatures (<±1 °C fluctuation) to preserve bacterial DNA integrity. Leveraging this system, a duplex qPCR assay was optimized for simultaneous quantitative detection of V. parahaemolyticus and V. cholerae in aquatic products and environmental samples. The assay demonstrated robust performance with 90–110% amplification efficiencies across diverse matrices, achieving low limits of detection (LODs) of 10¹–10² CFU/mL in shrimp farming environment water and 10²–10³ CFU/g in shrimp (Litopenaeus vannamei) and oyster (Crassostrea gigas). Notably, it effectively discriminated viable bacteria from 10⁶ CFU/mL(g) nonviable cells and showed strong correlation with ISO-standard methods in real-world sample validation. This integrated platform offers a rapid, automated solution for accurate viable bacterial quantification, with significant implications for food safety, pathogen surveillance, and risk management in aquatic industries. Full article

Climate change and ocean warming have a huge impact on microbial communities, leading to an increased prevalence of Vibrio parahaemolyticus infections in northern America. V. parahaemolyticus is an inhabitant of aquatic environments and is associated with fishes and shellfishes, particularly with oysters. It causes gastrointestinal infection through consumption of contaminated seafood, as well as wound infections or septicemia. Temperature is known to affect virulence and persistence factors in V. parahaemolyticus. In this study, twenty clinical strains isolated form sick patients in Quebec, Canada, were characterized for persistence and virulence factor production at different temperatures to assess the impact of a switch from sea water to the human body on them. Their capacity to produce biofilm, hemolysins, and membrane vesicles as well as their motility and antibiotic resistance at 20 °C and 37 °C were assessed. Our results revealed that while temperature had little effect on vesicle production, it significantly influenced their growth, antimicrobial resistance, biofilm formation, and motility. Additionally, all V. parahaemolyticus strains produced hemolysins at 37 °C but not under environmental conditions. Full article

Like other invertebrates, Litopenaeus vannamei lacks adaptive immunity and relies mainly on innate immunity for defense against foreign pathogens. In this study, three distinct Reeler domain-containing molecules were discovered in L. vannamei, designated as LvReeler1, LvReeler2, and LvReeler3. Analysis of tissue-specific expression patterns indicated that LvReeler1 showed predominant expression in the stomach, whereas LvReeler2 and LvReeler3 demonstrated peak transcriptional activity within gill tissues. The expression of these molecules was induced by Vibrio parahaemolyticus. In vivo interference with LvReelers expressions via dsRNA significantly increased the mortality rate of L. vannamei, while also leading to a marked increase in the bacterial load of V. parahaemolyticus in the gills. Additionally, recombinant proteins of LvReeler1 (rLvReeler1), LvReeler2 (rLvReeler2), and LvReeler3 (rLvReeler3) were successfully expressed in Escherichia coli. Antibacterial assays demonstrated that rLvReelers inhibited the growth of V. parahaemolyticus, Vibrio alginolyticus, and Vibrio harveyi, with rLvReeler3 exhibiting the strongest inhibitory activity. Scanning electron microscopy (SEM) observations revealed that rLvReeler3 caused bacterial aggregates to disintegrate after binding to V. parahaemolyticus and V. alginolyticus. In conclusion, LvReelers play an active role in the antimicrobial immune response of L. vannamei. Full article

Vibrio parahaemolyticus is a prevalent pathogen responsible for foodborne diseases in coastal regions. Understanding its dynamic relationship with various meteorological and marine factors is crucial for predicting outbreaks of bacterial foodborne illnesses. This study analyzes the occurrence of V. parahaemolyticus-induced foodborne illness in Zhejiang Province, China, from 2014 to 2018, using an 8-day time unit based on the temporal characteristics of marine products. The detection rate of V. parahaemolyticus exhibited a distinct cyclical pattern, peaking during the summer months. Meteorological and marine factors showed varying lag effects on the detection of V. parahaemolyticus, with specific lag periods as follows: sunshine duration (3 weeks), air temperature (3 weeks), total precipitation (8 weeks), relative humidity (7 weeks), sea surface temperature (1 week), and sea surface salinity (8 weeks). The SARIMAX model, which incorporates both marine and climatic factors, was developed to facilitate short-term forecasts of V. parahaemolyticus detection rates in coastal cities. The model’s performance was evaluated, and the actual values consistently fell within the 95% confidence interval of the predicted values, with a mean absolute error (MAE) of 0.047, indicating high accuracy. This framework provides both theoretical and practical insights for predicting and preventing future foodborne disease outbreaks. These findings can support food industry stakeholders—such as seafood suppliers, restaurants, regulatory agencies, and healthcare institutions—in anticipating high-risk periods and implementing targeted measures. These include enhancing cold chain management, conducting timely seafood inspections, strengthening cross-contamination controls during seafood processing, dynamically adjusting market surveillance intensity, and improving hygiene practices. In addition, hospitals and local health departments can use the model’s forecasts to allocate medical resources such as beds, medications, and staff in advance to better prepare for seasonal surges in foodborne illness. 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

This study explored the effectiveness of plasma-activated water (PAW), generated by a newly developed compact generator, for decontaminating foodborne bacteria in oyster meats. The generator effectively produced PAW with antibacterial activity when the water passed through the plasma reactor in a single cycle. The temperature of the PAW produced by the developed device did not exceed 40 °C, enabling its direct application to biological tissues immediately after production and discharge from the plasma reactor. The effects of flow rates and post-discharge times on key reactive species—including hydrogen peroxide, nitrite, and nitrate—were analyzed, along with pH and temperature. Freshly produced PAW can completely inhibit both E. coli and S. aureus in vitro, with a 5-log reduction within 5 min of treatment. Application to oyster meats led to an 86.6% and 87.9% inactivation of V. cholerae and V. parahaemolyticus, respectively. These research findings indicate that PAW generated using the developed compact flow-through generator holds promise as a food safety solution for households. The fact that complete foodborne pathogen elimination was not achieved emphasizes the need for further optimization. Full article

Vibrio parahaemolyticus is a foodborne pathogen commonly associated with the consumption of contaminated seafood, particularly oysters. While PCR and real-time PCR are widely used to detect its pathogenicity through tdh and trh gene detection, these methods may not be practical in resource-limited settings such as field environments. To address this limitation, a rapid, sensitive, and specific duplex detection method was developed using the multienzyme isothermal rapid amplification (MIRA) assay in combination with lateral flow dipstick (LFD) technology. The assay utilized specific primer sets and probes to simultaneously amplify tdh and trh fragments tagged with 3′-FAM and 5′-Digoxigenin or Biotin during MIRA amplification, enabling the detection via respective antibody capture on the LFD strip. This duplex MIRA-LFD assay demonstrated a detection limit of 100 fg of DNA, 300 CFU/reaction for bacterial culture, and 3000 CFU/reaction for seeded oyster samples at 40 °C within 20 min. Notably, the assay exhibited no cross-reactivity with nine other Vibrio species or 18 foodborne pathogens, confirming its high specificity. Due to its simplicity, rapid turnaround time, and high sensitivity, this duplex MIRA-LFD assay offers a valuable tool for the surveillance of V. parahaemolyticus pathogenicity, aiding in public health protection and supporting the local seafood industry. Full article