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This study aimed to perform in vitro antiparasitic and antimicrobial tests with the essential oil (EO) of Schinus terebinthifolius against of fish and shrimp. The chemical composition of the EO of S. terebinthifolius was determined by gas chromatography. For the antiparasitic test, the protozoan Epistylis sp. obtained from parasitized Oreochromis niloticus was used, and exposed to different concentrations of EO (2%, 1%, 0.5%, 0.25%), and control with 1% grain alcohol. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) test with EO of S. terebinthifolius evaluated the antimicrobial potential, with serial dilutions starting at 2% and control with 1% grain alcohol, using the strains of Aeromonas hydrophila (2.2 × 108 CFU mL−1), Edwardsiella tarda, Vibrio parahaemolyticus, V. harveyi, and V. alginolyticus (2.0 × 108 CFU mL−1). Chemical analysis revealed that the major EO compounds of S. terebinthifolius were δ‐3‐Carene (56.00%) and α‐Pinene (16.89%). In the antiparasitic test, the concentration of 2% EO showed 100% efficacy against Epistylis sp. within 5 min. In the antimicrobial tests, the concentration of 2% EO was effective against all bacteria tested. The EO of S. terebinthifolius demonstrated antiparasitic and antimicrobial activity at a concentration of 2%, standing out as an alternative to conventional antibiotics. [ABSTRACT FROM AUTHOR]

Black bean skin anthocyanins (BBSAs), as by‐products of black beans, have not been fully exploited. BBSAs are rich in anthocyanins and have a wide range of health benefits. In this study, the antibacterial and antibiofilm action mode of BBSAs against Vibrio parahaemolyticus (V. parahaemolyticus) was evaluated. The antibacterial and antibiofilm efficiency was evaluated under different conditions, shedding light on their mode of action against V. parahaemolyticus. The results showed that the inactivation efficacy of BBSAs on V. parahaemolyticus was positively correlated with its concentration and incubating time. The MIC value for BBSAs was determined to be 10 μg/mL. The formation of V. parahaemolyticus biofilm was hindered by the presence of the BBSAs, especially at higher concentrations of BBSAs and during the early intervention stage. After exposure to 1 MIC of BBSA, the inhibition rate of biofilm reached 91.94%. The release of cellular components and alterations in membrane morphology indicated that BBSAs can damage the integrity of V. parahaemolyticus cell membrane. Furthermore, BBSAs may interact with membrane proteins, causing a notable conformational change in membrane proteins. HPLC and UPLC‐MS analysis confirmed that the major antibacterial compound in BBSAs was Cyanidin‐3‐O‐glucoside (C3G), which can form a stable complex with LolB protein in the outer membrane via hydrogen bonding. This study can provide strong technical support for the accurate control of V. parahaemolyticus and pave the way for the application of natural antibacterial agents in the realm of food‐borne bacterial control. [ABSTRACT FROM AUTHOR]

Early mortality syndrome (EMS) or acute hepatopancreatic necrosis syndrome (AHPND) is an epizootic bacterial infection of shrimp that has had significant negative impact on the global shrimp aquaculture industry. This disease is largely attributed to pathogenic Vibrio parahaemolyticus EMS strains (VP‐EMS). Application of probiotics was examined for control of pathogenic VP‐EMS infections in Pacific white shrimp (Litopenaeus vannamei) under laboratory‐scale conditions. Two probiotic products, a single strain (O14VRQ) of Bacillus subtilis and a blend (Plus10) of five strains of Bacillus from four different species (Bacillus amyloliquifaciens, Bacillus megaterium, Bacillus brevis, and two distinct strains of Bacillus subtilis), were evaluated at various concentrations as feed additives (applied as a top coat on commercial feed) or dosed directly into the culture water. Two trials were conducted in which shrimp were fed either a control feed (no probiotics) or probiotic‐coated feed for 7 days prior to be being challenged with VP‐EMS. Shrimp were observed for clinical signs of disease and mortalities during the disease challenge study. These experiments demonstrated that while both Bacillus probiotic products were shown to significantly (p < 0.05) improve shrimp survival, the O14VRQ strain provided the most consistent protection across the trials in top‐coated feed. Overall, better efficacy was observed with probiotic‐coated feeds. Findings were directly and positively correlated with concentration for top‐coated and even more so for direct in‐tank applications. Collectively, these findings contribute to our understanding about how probiotic strains could be applied to enhance shrimp health in aquaculture. [ABSTRACT FROM AUTHOR]

This perspective article primarily discusses the role of water matrix for the advanced treatment of watercourses. This relies on experimental work regarding the inactivation of Escherichia coli, Enterococcus faecalis, and Vibrio parahaemolyticus by an advanced oxidation process, namely activated persulfate, in five matrices of varying complexity, (i.e., from as simple as deionized water to secondary treated effluent). For comparison purposes, respective tests were performed with ultraviolet (UVC) radiation, a conventional disinfection process, while results from recent literature are also discussed. Only in deionized water can activated persulfate (i.e., 150 mg L−1 sodium persulfate and 30 mg L−1 ferrous ions) completely inactivate all three bacteria in the course of several minutes, but the process is ineffective in other matrices (i.e., bottled, tap, or lake water, as well as wastewater), where 1–2 orders of magnitude longer times are needed for partial inactivation, which decreases in the order E. coli > E. faecalis ~ V. parahaemolyticus. Conversely, UVC (at 30 W nominal value) is highly efficient against all bacteria and in all matrices in a matter of just a few seconds. The general perception is that treatment efficiency decreases with increasing matrix complexity in terms of total concentration and/or individual components composition, irrespective of the applied treatment method and its objectives (i.e., disinfection, decontamination, or mineralization). However, there are always exceptions the rule, further highlighting how case‐specific advanced water treatment can be. The matrix itself should be given particular emphasis for the rational design of efficient water treatment processes. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Tilapia stands out as one of the most extensively farmed and consumed fish species globally, valued for its ease of preparation and relative affordability. Although tilapia is a valuable protein source, it can also function as a vector for foodborne pathogens. This literature review reveals that tilapia could carry a variety of contamination with various foodborne pathogens, including Plesiomonas shigelloides, diarrheagenic Escherichia coli, Vibrio parahaemolyticus, Salmonella Weltevreden, Salmonella enterica, Shigella, Staphylococcus aureus, Campylobacter jejuni, Clostridium botulinum, and Listeria monocytogenes. Although guidelines from entities, such as the Global Seafood Alliance, Aquaculture Stewardship Council, and International Organization for Standardization, have been established to ensure the microbiological safety of tilapia, the unique challenges posed by pathogens in tilapia farming call for a more nuanced and targeted approach. Recognizing that contaminants could emerge at various stages of the tilapia supply chain, there is a crucial need for enhanced detection and monitoring of pathogens associated with this fish and its culturing environment. Additionally, it is essential to acknowledge the potential impact of climate change on the safety of tilapia, which may elevate the prevalence and contamination levels of pathogens in this fish. Proactive measures are essential to understand and mitigate the effects of climate change on tilapia production, ensuring the sustainability and safety of this seafood product for both present and future generations. [ABSTRACT FROM AUTHOR]

This study aims to develop an alternative aquafeed derived from insect meal for Lates calcarifer juveniles, with the objectives of exploring the physiological performance, biological parameters, and economic analysis of substituting fishmeal (FM) with defatted black soldier fly (Hermetia illucens) larvae (BSFL) as part of the diet of L. calcarifer juveniles. Five practical diets were formulated to include 0% (BSFL0, serves as control group), 5% (BSFL5), 10% (BSFL10), 15% (BSFL15), and 20% (BSFL20) of BSFL meal, partially or fully replacing FM, respectively. Each diet was randomly assigned to triplicate groups of 30 fish (10.70 ± 0.07 g) per tank (300 L). The fish were fed twice daily to apparent satiation. A 56‐day feeding trial was conducted to evaluate the impacts of defatted BSFL meal replacing FM on the growth performance, feed efficiency, composition analysis of fish muscle, cumulative mortality rate challenged with Vibrio parahaemolyticus, and economic returns of L. calcarifer. These results show that differences in weight gain and specific growth rate among the different treatments were statistically significant (p < 0.05), except for the absence of significant variation (p < 0.05) between BSFL0 and BSFL5, and followed by BSFL10 > BSFL0 > BSFL5 > BSFL15 > BSFL20. However, the feed conversion ratio and protein efficiency ratio showed the opposite trend as above. Although the diets experienced a decline in crude protein content and an increase in crude fat content with the increasing proportion of BSFL substituting FM, the crude protein and fat content of fish muscle were only slightly influenced. It is worth mentioning that levels of nonessential amino acids, delicious amino acids, saturated fatty acids, omega‐6, omega‐9 in BSFL10 group all showed an increase compared with the control group. After a 7‐day challenge test with V. parahaemolyticus, the cumulative mortality rates of the BSFL5 and BSFL10 groups, respectively, dropped to 5.20%, 5.28% compared to the control group's 16.88%; however, the mortality rates of BSFL15 (34.67%) and BSFL20 (41.77%) groups were found to be significantly (p < 0.05) increased. From an economic perspective, the incidence cost for each experimental group showed a trend as BSFL10 < BSFL0 < BSFL5 < BSFL15 < BSFL20, whereas the profit index in each treatment exhibited the opposite trend as above. It was concluded that low (5%) or moderate (10%) levels of BSFL substituting FM in aquaculture feed could improve the physiological performances, disease resistance, and economic returns of L. calcarifer. However, excessive substitution (>15%) leads to a negative effect. From an economic point of view, 10% inclusion of BSFL in practical diets is recommended for L. calcarifer juveniles. [ABSTRACT FROM AUTHOR]

The incidence of vibriosis is rising globally with evidence of climate variability influencing environmental processes that support growth of pathogenic Vibrio spp. The waterborne pathogen, Vibrio vulnificus can invade wounds and has one of the highest case fatality rates in humans. The bacterium cannot be eradicated from the aquatic environment, hence climate driven environmental conditions enhancing growth and dissemination of V. vulnificus need to be understood to provide preemptive assessment of its presence and distribution in aquatic systems. To achieve this objective, satellite remote sensing was employed to quantify the association of sea surface temperature (SST) and chlorophyll‐a (chl‐a) in locations with reported V. vulnificus infections. Monthly analysis was done in two populated regions of the Gulf of Mexico—Tampa Bay, Florida, and Galveston Bay, Texas. Results indicate warm water, characterized by a 2‐month lag in SST, high concentration of phytoplankton, proxied for zooplankton using 1 month lagged chl‐a values, was statistically linked to higher odds of V. vulnificus infection in the human population. Identification of climate and ecological processes thresholds is concluded to be useful for development of an heuristic prediction system designed to determine risk of infection for coastal populations. Plain Language Summary: Our study focused on Vibrio spp., a group of bacteria in warm, slightly salty water. One of these, Vibrio vulnificus, is especially dangerous and can cause severe illness with a high risk of death. The spread of this pathogen in humans is becoming more of a concern due to climate change. We aimed to understand what environmental conditions influence occurrence of the disease caused by this bacterium. The main factor linked to the rise of V. vulnificus is sea surface temperature (SST). However, other factors like chlorophyll also play a role. We used satellite data to monitor SST and chlorophyll levels and statistically associated this data with the number of people getting sick from V. vulnificus. Our findings indicate a pattern: when 2 months prior SST and 1‐month prior chlorophyll levels are higher than their monthly average, the chance of V. vulnificus infections is higher. By using this pattern, we aim to predict better when and where infections might happen, helping identify at‐risk areas and potentially stop outbreaks before they occur. Key Points: Likelihood of Vibrio vulnificus infections is influenced by elevated Sea Surface Temperature and chlorophyll of previous monthsSea Surface Temperature, chlorophyll, and V. vulnificus cases occurrence showed increasing trends during the study periodStatistically significant difference was observed between overall chlorophyll levels and the levels recorded during increased cases of V. vulnificus [ABSTRACT FROM AUTHOR]

Summary: This study delved into the antimicrobial potential of hydrolysates from adzuki bean and mung bean protein concentrates, created using Alcalase and Flavourzyme enzymes. Targeting common foodborne pathogens (Salmonella Typhimurium, Salmonella Enteritidis, Vibrio parahaemolyticus, Staphylococcus aureus, and Bacillus subtilis) and Escherichia coli, the research underscored the crucial role of peptidase in generating antibacterial peptides. Fractions F2 of Flavourzyme hydrolysed adzuki bean (ABF) and F4 of Flavourzyme hydrolysed mung bean (MBF) showed the highest antibacterial activity against S. Typhimurium and S. aureus, respectively, whereas F2 of Alcalase hydrolysed mung bean (MBA) exhibited very poor activity against S. aureus. TripleTOF LC–MS/MS analysis revealed small cationic antibacterial peptides, with lysine being prominent against S. aureus and proline–proline against S. Typhimurium. These findings highlighted the significant contribution of protease enzymes in fostering antibacterial peptide production, offering valuable insights for developing effective antimicrobial agents in the context of food safety. [ABSTRACT FROM AUTHOR]

Given the growing global demand for seafood, it is imperative to conduct a comprehensive study on the prevalence and persistence patterns of pathogenic bacteria and viruses associated with specific seafood varieties. This assessment thoroughly examines the safety of seafood products, considering the diverse processing methods employed in the industry. The importance of understanding the behavior of foodborne pathogens, such as Salmonella typhimurium, Vibrio parahaemolyticus, Clostridium botulinum, Listeria monocytogenes, human norovirus, and hepatitis A virus, is emphasized by recent cases of gastroenteritis outbreaks linked to contaminated seafood. This analysis examines outbreaks linked to seafood in the United States and globally, with a particular emphasis on the health concerns posed by pathogenic bacteria and viruses to consumers. Ensuring the safety of seafood is crucial since it directly relates to consumer preferences on sustainability, food safety, provenance, and availability. The review focuses on assessing the frequency, growth, and durability of infections that arise during the processing of seafood. It utilizes next‐generation sequencing to identify the bacteria responsible for these illnesses. Additionally, it analyzes methods for preventing and intervening of infections while also considering the forthcoming challenges in ensuring the microbiological safety of seafood products. This evaluation emphasizes the significance of the seafood processing industry in promptly responding to evolving consumer preferences by offering current information on seafood hazards and future consumption patterns. To ensure the continuous safety and sustainable future of seafood products, it is crucial to identify and address possible threats. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate and unveil the positive impact of biofloc culture on Vibrio parahaemolyticus infection of Pacific white shrimp by reducing quorum sensing (QS) and virulence gene expression and enhancing shrimp's immunity. The shrimp with an average body weight of 0.50 ± 0.09 g were reared in containers with a volume of 2.5 L, 21 units, and a density of 20 shrimp L−1. The shrimp were cultured for 5 days, with each treatment including biofloc system maintenance with a C/N ratio of 10 and a control treatment without biofloc, followed by a challenge test through immersion using V. parahaemolyticus at densities of 103, 105, and 107 CFU mL−1 initially. The results of the in vitro experiment showed that biofloc suspension can inhibit and disperse biofilm formation, as well as reduce the exo‐enzyme activity (amylase, protease, and chitinase) of V. parahaemolyticus. Furthermore, the biofloc treatment significantly reduced the expression of the QS regulatory gene OpaR, the PirB toxin gene, and the virulence factor genes T6SS1 and T6SS2 in both in vitro and in vivo. The biofloc system also increased the expression of shrimp immunity‐related genes (LGBP, proPO, SP, and PE) and the survival rate of white shrimp challenged with V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

Vibrio harveyi and Vibrio parahaemolyticus are species of the Vibrio genus that often cause disease and mass mortality in crustaceans. If not handled quickly and appropriately, these diseases can cause considerable losses to farmers. Therefore, it is necessary to find a solution with safe and environmentally friendly disease prevention technology using natural ingredients, among others from plants, namely oil palm. Some parts of oil palm, namely leaves, fronds, fibres and oil palm pulp, which are palm waste, contain antibacterial compounds. This study aimed to assess the antibacterial activity of palm waste extracts, namely pulp, leaves, fronds and fibres using n‐hexane, ethyl acetate, chloroform, ethanol and water maceration solvents against pathogenic bacteria V. harveyi and V. parahaemolyticus, and identify active compounds contained in palm waste. The results of the research are expected to produce innovative and sustainable solutions to control diseases in shrimp farming, contribute to the development of a sustainable fishing industry and open up the potential for utilizing palm waste as a value‐added resource in the field of aquatic health. The results of observations on antibacterial activity tests and identifying the content of palm waste extract compounds were analysed descriptively displayed in the form of figures, tables and graphs. The results showed that palm waste extracts (pulp, leaves, fronds and fibres) with ethyl acetate and ethanol maceration solvents had very strong antibacterial potential, namely 20.14 ± 0.31 mm–25.52 ± 1.42 mm on V. harveyi bacteria and 20.41 ± 0.55 mm–25.00 ± 0.51 mm on V. parahaemolyticus bacteria. Palm extracts with n‐hexane (>20 mm) and chloroform solvents generally have strong category antibacterial potential (10–20 mm), and palm extracts in water solvents have medium category potential (5–10 mm) against V. harveyi and V. parahemolyticus bacteria. The results of phytochemical tests on palm waste extracts with ethyl acetate and ethanol maceration solvents contain bioactive compounds of flavonoids, saponins, polyphenols and alkaloid tannins, steroids and triterpenoids. Palm extracts with n‐hexane and chloroform solvents generally contain saponins, alkaloids, steroids and triterpenoids, while palm waste extracts with water solvents contain saponins. [ABSTRACT FROM AUTHOR]

This study investigated the disparities in soil characteristics and pathogenic bacteria prevalence between shrimp ponds affected by acute hepatopancreatic necrosis disease (AHPND) and unaffected ponds, alongside examining the spatial distribution of soil attributes in flat‐oriented pond soil strata. Using Pearson correlation and logistic regression analyses, relationships among variables and indicators associated with AHPND prevalence were discerned, leading to the formulation of a predictive model for AHPND occurrence. Soil samples were collected from distinct locations and depths within ponds across three southern provinces of Thailand's Andaman Seaboard. The analysis revealed significantly higher concentrations of several variables, including SOD, TIC, NO2−‐N, Ca, Mn, Cu, Zn, and specified Vibrio strains, in AHPND‐afflicted ponds, especially at 0–5 cm depth. A prominent differentiation was the escalated concentration of easily decomposable organic matter (EDOM) within infected ponds, implicating potential soil and water quality deterioration alongside heightened shrimp susceptibility to AHPND. Correlational analysis showed links between bacterial densities and organic matter groupings, trace elements, exchangeable bases, and soil pH, in AHPND‐infected ponds. The logistic regression model encapsulated three soil variables (TOC, Mg, and Mn) and one pathogen variable (V. parahaemolyticus) and furnished an equation to estimate the log (odds) of AHPND occurrence, facilitating better understanding and potential forecasting of AHPND prevalence in shrimp cultivation environments. [ABSTRACT FROM AUTHOR]

Vibrios, a group of bacteria that are among the most abundant in marine environments, include several species such as Vibrio cholerae and Vibrio parahaemolyticus, which can be pathogenic to humans. Some species of Vibrio contain prophages within their genomes. These prophages can carry genes that code for toxins, such as the zonula occludens toxin (Zot), which contribute to bacterial virulence. Understanding the association between different Vibrio species, prophages and Zot genes can provide insights into their ecological interactions. In this study, we evaluated 4619 Vibrio genomes from 127 species to detect the presence of prophages carrying the Zot toxin. We found 2030 potential prophages with zot‐like genes in 43 Vibrio species, showing a non‐random association within a primarily modular interaction network. Some prophages, such as CTX or Vf33, were associated with specific species. In contrast, prophages phiVCY and VfO3K6 were found in 28 and 20 Vibrio species, respectively. We also identified six clusters of Zot‐like sequences in prophages, with the ZOT2 cluster being the most frequent, present in 34 Vibrio species. This analysis helps to understand the distribution patterns of zot‐containing prophages across Vibrio genomes and the potential routes of Zot‐like toxin dissemination. [ABSTRACT FROM AUTHOR]

This article provides information on Acute Hepatopancreatic Necrosis Disease (AHPND), a bacterial disease that has had a significant impact on the shrimp farming industry. The main causative agent of AHPND is Vibrio parahaemolyticus, but other Vibrio strains with similar toxin genes have also been reported. The article focuses on the identification and evaluation of a novel Vibrio strain isolated from a shrimp farm in South Korea. The strain, known as HJ-2023, was found to be highly virulent and resistant to certain antibiotics. The research emphasizes the importance of biosecurity measures to prevent the spread of AHPND in aquaculture. [Extracted from the article]

As acute gastrointestinal (AGI) disease patients only sometimes seek medical care or submit stool samples for testing, and laboratories cannot detect or identify the pathogen, most cases of foodborne gastroenteritis still need to be identified through public health monitoring. We conducted a population survey and sentinel hospital surveillance to determine the burden of foodborne gastroenteritis caused by non‐typhoidal Salmonella enterica (NTS) and Vibrio parahaemolyticus infection, from July 2018 to June 2019 in Zhejiang province, China, and a model for calculating disease burden established. Using the burden of illness pyramid model, we estimated that there were 140.3 cases of NTS infection and 136.2 cases of V. parahaemolyticus infection. We estimated annual incidence per 100,000 population in Zhejiang province as 236 (95% confidence interval [CI] 208–267) and 206 (95% CI 155–232) cases for foodborne NTS and V. parahaemolyticus gastroenteritis, respectively. The results show that AGI caused by these two pathogens constitutes a substantial burden in the Zhejiang population. The health burden of AGI estimations caused by NTS and V. parahaemolyticus in this study can serve as a strategic framework to direct policy and intervention. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus (V. parahaemolyticus) is a major pathogen that causes substantial losses in the marine fishery. With the emergence of antibiotic resistance, vaccines have become the most effective approach against V. parahaemolyticus infection. Adhesion factors on the cell surface are pivotal in the colonization and pathogenesis of V. parahaemolyticus within the host, highlighting their potential as vaccine candidates. This study aims to assess the immunogenicity and potential of recombinant V. parahaemolyticus MAM7 (rMAM7) as a vaccine candidate. Initially, we cloned and purified the MAM7 protein of V. parahaemolyticus. Moreover, after 4 weeks of vaccination, the fish were challenged with V. parahaemolyticus. rMAM7 demonstrated a certain protective effect. Immunological analysis revealed that rMAM7 immunization‐induced antibody production and significantly increased acid phosphatase (ACP) and alkaline phosphatase (AKP) activity in hybrid tilapia. Furthermore, serum bactericidal tests demonstrated a lower bacterial survival rate in the rMAM7 group compared to PBS and rTrxa. qRT‐PCR results indicated that rMAM7 significantly upregulated CD4, CD8 and IgM gene expression, suggesting the induction of Th1 and Th2 responses in hybrid tilapia. Overall, these findings highlight the potential application of MAM7 from V. parahaemolyticus in the development of protein vaccines. [ABSTRACT FROM AUTHOR]

Acute Hepatopancreatic Necrosis Disease (AHPND) represents a significant challenge in the field of shrimp aquaculture. This disease is primarily caused by Vibrio parahaemolyticus strains harbouring the pVA1 plasmid encoding the PirAvp and PirBvp toxins. To combat this epidemic and mitigate its devastating consequences, it is crucial to identify and characterize the receptors responsible for the binding of these pathogenic toxins. Our studied discovered that Penaeus vannamei's Serine protease inhibitor 3 (PvSerpin3) derived from shrimp hepatopancreatic tissues could bind to recombinant PirAvp, confirming its role as a novel PirAvp‐binding protein (PABP). Through comprehensive computational methods, we revealed two truncated PirAvp–binding proteins derived from PvSerpin3 called Serpin3(13) and Serpin3(22), which had higher affinity to PirAvp than the full‐length PvSerpin3. The PABP genes were amplified from a cDNA library that was reversed from total RNA extracted from shrimp, cloned and expressed in Escherichia coli. Three PABP inclusion bodies were refolded to obtain the soluble form, and the recovery efficacy was found to be 100% for Serpin3 and Serpin3(13), while Serpin3(22) had a recovery efficacy of roundly 50%. Co‐Immunoprecipitation (co‐IP) and dot blot assays substantiated the interaction of these recombinant PABPs with both recombinant PirAvp and VPAHPND (XN89)‐producing natural toxins. [ABSTRACT FROM AUTHOR]

The protein profiles of bacteria are useful markers in their identification. In this study, we examined the influence of environmental settings on the protein profiles of culturable bacteria using matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI–TOF MS). We compared the protein profiles of bacteria collected from geographically distinct port environments (Kolkata, a freshwater port, and Kandla, a marine port) from India. The results indicated that bacterial species were distinctly different between the two ports, except for a few bacteria, that were common, such as Bacillus cereus, Enterobacter cloacae, Micrococcus luteus, Pseudomonas aeruginosa, P. putida, P. stutzeri, P. mosselii and Vibrio parahaemolyticus. Mass spectra of these common bacterial species, a few pathogenic among them, differed in their protein profiles and relative intensity of peaks. These variations point out that environmental settings/factors have a significant role in the protein expression and can result in differentiated virulence of pathogens. Identifying these risk factors is crucial in developing appropriate environmental port management practices. [ABSTRACT FROM AUTHOR]

The phosphoinositide‐3‐kinase/protein kinase b (PI3K‐Akt) pathway is a signalling pathway based on protein phosphorylation and can be activated by a wide range of factors. To investigate the function of the PI3K‐AKT signalling pathway in antibacterial immunity, we analysed the gene expression level of three key factors (PI3K, AKT and FoxO) and innate immune factors in immune tissues at different time points after Vibrio parahaemolyticus and Staphylococcus aureus infection. Tissues analysis showed that PI3K, AKT, and FoxO were expressed at high levels in the intestinal, hemocytes and hepatopancreas. Moreover, the expression levels of PI3K, AKT and FoxO can be regulated postinfection by different pathogens. In hemocytes and the intestine, V. parahaemolyticus infection was found to regulate the levels of PI3K, AKT, and FoxO more rapidly; however, an S. aureus infection regulated the levels of these factors more rapidly in the hepatopancreas and gills. Analysis showed that V. parahaemolyticus and S. aureus infection caused changes in the gene expression level of crustin, caspase 3 and NF‐κB. Therefore, PI3K‐AKT regulates the downstream immune pathway differentially in different immune tissues and participates in the regulation of cell apoptosis and the inflammatory response by activating caspase and NF‐κB, respectively, following infection with V. parahaemolyticus and S. aureus. [ABSTRACT FROM AUTHOR]

Vibrio aestuarianus is a bacterium related to mass mortality outbreaks of the Pacific oyster, Crassostrea gigas in Europe. In this study, the role of different planktonic substrates (phytoplankton cells, marine aggregates and chitin fragments) in mediating V. aestuarianus 02/041 infection of oysters was evaluated by controlled infection experiments. It was shown that phytoplankton cells and, to a greater extent, marine aggregates, significantly promote V. aestuarianus 02/041 intake by C. gigas maintained under stressful conditions in the laboratory. Such intake is associated with higher concentration of the pathogen in the bivalve hemolymph and compromised health status of infected oysters. In contrast, chitin particles do not play a significant role as transmission vector for V. aestuarianus 02/041 infecting its bivalve host. Interestingly, incorporation into marine aggregates foster extracellular proteases (ECPs) activity and a higher expression of bacterial virulence genes, that are potentially involved in bivalve infection. Results from this study contribute to elucidate transmission patterns of V. aestuarianus 02/041 to C. gigas that may be useful for the development of efficient measures to prevent and control oyster disease outbreaks. [ABSTRACT FROM AUTHOR]

Thermostable direct haemolysin (TDH) is the key virulence factor secreted by the human gastroenteric bacterial pathogen Vibrio parahaemolyticus. TDH is a membrane‐damaging pore‐forming toxin. It evokes potent cytotoxicity, the mechanism of which still remains under‐explored. Here, we have elucidated the mechanistic details of cell death response elicited by TDH. Employing Caco‐2 intestinal epithelial cells and THP‐1 monocytic cells, we show that TDH induces some of the hallmark features of apoptosis‐like programmed cell death. TDH triggers caspase‐3 and 7 activations in the THP‐1 cells, while caspase‐7 activation is observed in the Caco‐2 cells. Interestingly, TDH appears to induce caspase‐independent cell death. Higher XIAP level and lower Smac/Diablo level upon TDH intoxication provide plausible explanation for the functional inability of caspases in the THP‐1 cells, in particular. Further exploration reveals that mitochondria play a central role in the TDH‐induced cell death. TDH triggers mitochondrial damage, resulting in the release of AIF and endonuclease G, responsible for the execution of caspase‐independent cell death. Among the other critical mediators of cell death, ROS is found to play an important role in the THP‐1 cells, while PARP‐1 appears to play a critical role in the Caco‐2 cells. Altogether, our work provides critical new insights into the mechanism of cell death induction by TDH, showing a common central theme of non‐classical programmed cell death. Our study also unravels the interplay of crucial molecules in the underlying signalling processes. Our findings add valuable insights into the role of TDH in the context of the host–pathogen interaction processes. [ABSTRACT FROM AUTHOR]

Objectives: This study was to identify and characterize Decapod iridescent virus 1 (DIV1) in the outbreaks reported in two whiteleg shrimp farms and one black tiger shrimp farm located in northern Taiwan in 2020. Methods: The histopathology, electron microscopy and polymerase chain reaction (PCR) specific for the DIV1 were used to identify the virus, and the phylogenetic analysis was performed by comparing the major capsid protein gene fragment of DIV1s from Taiwan with reference sequences of the family Iridoviridae. Results: DIV1 was identified by diagnostic PCR and caused mild mortality (20%) in cultured Penaeus monodon and high mortality (100%) in cultured whiteleg shrimp. Cultured P. monodon was first found to be infected with DIV1 through natural route of infection. Histopathological examination showed dark‐eosinophilic cytoplasmic inclusions in the degenerative cells of targeted hematopoietic tissues. For electron microscopy, a non‐enveloped virus particle was observed from homogenates of mixed target organs through negative staining with a diameter of 112±2 nm. Nucleotide sequences of DIV1 isolates from the Taiwanese outbreak are 100% identical to those from the PRC. Conclusions: Based on the clinical evidence, mortality rates, histopathology, electron microscopy examinations and phylogenetic analysis, it is believed that DIV1 is the causative agent of the outbreak. This is the first report of DIV1 in cultured shrimp in Taiwan. The emergence of DIV1 signals a warning to shrimp aquaculture farmers worldwide. [ABSTRACT FROM AUTHOR]

Phages depend on their bacterial hosts to replicate. The habitat, density and genetic diversity of host populations are therefore key factors in phage ecology, but our ability to explore their biology depends on the isolation of a diverse and representative collection of phages from different sources. Here, we compared two populations of marine bacterial hosts and their phages collected during a time series sampling program in an oyster farm. The population of Vibrio crassostreae, a species associated specifically to oysters, was genetically structured into clades of near clonal strains, leading to the isolation of closely related phages forming large modules in phage–bacterial infection networks. For Vibrio chagasii, which blooms in the water column, a lower number of closely related hosts and a higher diversity of isolated phages resulted in small modules in the phage–bacterial infection network. Over time, phage load was correlated with V. chagasii abundance, indicating a role of host blooms in driving phage abundance. Genetic experiments further demonstrated that these phage blooms can generate epigenetic and genetic variability that can counteract host defence systems. These results highlight the importance of considering both the environmental dynamics and the genetic structure of the host when interpreting phage–bacteria networks. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a significant food‐borne pathogen that is found in diverse aquatic habitats. Quorum sensing (QS), a signaling system for cell–cell communication, plays an important role in V. parahaemolyticus persistence. We characterized the function of three V. parahaemolyticus QS signal synthases, CqsAvp, LuxMvp, and LuxSvp, and show that they are essential to activate QS and regulate swarming. We found that CqsAvp, LuxMvp, and LuxSvp activate a QS bioluminescence reporter through OpaR. However, V. parahaemolyticus exhibits swarming defects in the absence of CqsAvp, LuxMvp, and LuxSvp, but not OpaR. The swarming defect of this synthase mutant (termed Δ3AI) was recovered by overexpressing either LuxOvpD47A, a mimic of dephosphorylated LuxOvp mutant, or the scrABC operon. CqsAvp, LuxMvp, and LuxSvp inhibit lateral flagellar (laf) gene expression by inhibiting the phosphorylation of LuxOvp and the expression of scrABC. Phosphorylated LuxOvp enhances laf gene expression in a mechanism that involves modulating c‐di‐GMP levels. However, enhancing swarming requires phosphorylated and dephosphorylated LuxOvp which is regulated by the QS signals that are synthesized by CqsAvp, LuxMvp, and LuxSvp. The data presented here suggest an important strategy of swarming regulation by the integration of QS and c‐di‐GMP signaling pathways in V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a significant causal agent of acute hepatopancreatic necrosis disease (AHPND), with huge production losses of white leg shrimp, Litopenaeus vannamei, cultivated globally, including aquaculture farms in the Mekong Delta of Vietnam. Controlling this disease is critical because of the worldwide expansion of antimicrobial‐resistant V. parahaemolyticus isolates. The purpose of this study was to determine the frequency of multi‐antibiotic resistance (MAR) in V. parahaemolyticus isolated from AHPND white leg shrimp extensively cultivated in Bac Lieu Province (Mekong Delta). Based on biochemical tests and toxR‐PCR positive detections, 34 V. parahaemolyticus isolates were identified. Antibiotic susceptibility examination revealed that most of the isolates were phenotypically multidrug resistant, including resistance to ceftazidime (100%) and amoxicillin (97.06%), followed by colistin (74%) and erythromycin (65%). These isolates were highly sensitive to doxycycline (94%), followed by florfenicol (74%) and flumequine (71%). There were 27 distinct MAR phenotypes detected among 34 isolates, with 14.71% of the isolates exhibiting the antibiotic profile AMO‐CEF‐CEP‐COL‐ERY, followed by 11.76% for each of the profiles AMO‐CEP‐TET‐COL and AMO–CEP–COL. In particular, 25 isolates (75%) were resistant to at least 5 (of the 12) antibiotics tested. A hierarchical clustering analysis of antibiotic‐resistant V. parahaemolyticus isolates indicated cross‐transmission across farms and its ability to survive in aquatic environments for extended periods (over 3 months). Our findings support the hypothesis that the variety of MARPs in V. parahaemolyticus is the result of human activities. Environmentally friendly therapy strategies should be used for the prophylaxis and treatment of V. parahaemolyticus infection. [ABSTRACT FROM AUTHOR]

Shrimp is one of the most important aquatic products in the world. Early detection, prevention, and treatment of shrimp pathogens is important. One major shrimp pathogen, Vibrio parahaemolyticus causes acute hepatopancreatic necrosis disease (VPAHPND) has been studied, but research into pathogen detection needs to be strengthened. Therefore, we were targeting to VPAHPND and using emerging molecular biotechnologies to develop a method for pathogens detection for the shrimp industry. Gold nanoparticles (AuNPs) have an unique color change property. Free AuNPs in solution are the color of claret‐red, while the aggregated AuNPs appear slight purple. Based on the characteristics of visible color difference of AuNPs, we worked on establishing a simple, fast, and specific loop‐mediated isothermal amplification (LAMP) detection method for VPAHPND diagnosis using AuNPs. This method, amplified the target DNA of VPAHPND by LAMP and the DNA were directly added onto AuNPs solution for detection. The test results show a color change, so that the results can be visually inspected by naked eye. Using the methods, shrimp VPAHPND can be early detected and treated, boost the economic benefits, and efficiency of shrimp farming. [ABSTRACT FROM AUTHOR]

Vibrios belonging to the Harveyi clade (including closely related species such as Vibrio campbellii, Vibrio harveyi and Vibrio parahaemolyticus) are important pathogens of aquatic organisms. In this study, we investigated the use of indole‐3‐acetic acid to control disease caused by Harveyi clade vibrios. Indole‐3‐acetic acid, which can be produced by various seaweeds and microalgae, was added to the rearing water of brine shrimp larvae challenged with 12 different Harveyi clade Vibrio strains. Indole‐3‐acetic acid significantly decreased the virulence of 10 of the strains without any effect on their growth. The latter is important as it will minimize the selective pressure for resistance development. The survival rate of brine shrimp larvae increased from 1.2‐fold to 4.8‐fold upon treatment with 400 μM indole‐3‐acetic acid. Additionally, indole‐3‐acetic acid significantly decreased the swimming motility in 10 of the strains and biofilm formation in eight of the strains. The mRNA levels of the pirA and pirB toxin genes were decreased to 46% and 42% by indole‐3‐acetic acid in the AHPND‐causing strain V. parahaemolyticus M0904. Hence, our data demonstrate that indole‐3‐acetic acid has the potential to be an effective virulence inhibitor to control infections in aquaculture. [ABSTRACT FROM AUTHOR]

Four secondary acyltransferases of Vibrio parahaemolyticus lipid A encoded by VP_RS00880, VP_RS08405, VP_RS12170, and VP_RS01045 have been identified. In this study, mutants of V. parahaemolyticus were constructed by deleting two, three, or four of these genes. The double mutants showed similar growth pattern with the wild‐type, but the quadruple mutant VPW011 showed significant growth defect at both 37°C and 21°C. Lipid A samples were extracted from these mutants and analyzed by electrospray ionization‐mass spectrometry. The double and triple mutants could synthesize hepta‐ and octa‐acylated lipid A species, while the quadruple mutant VPW011 could synthesize hexa‐ and hepta‐acylated lipid A. The results suggest that the four secondary acyltransferases could complement each other in V. parahaemolyticus. More importantly, additional secondary acyltransferases of lipid A might exist in V. parahaemolyticus and their activities might be as strong as the four known secondary acyltransferases. The unusual multiple secondary acyltransferases of lipid A might play roles in pathogenicity and antimicrobic resistance of V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

Climate‐induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased Vibrio spread, exposure, and infection rates, thus facilitating greater Vibrio‐human interactions. Multiple efforts have been developed to predict Vibrio exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on V. vulnificus and V. parahaemolyticus planktonic and biofilm growth. Vibrio strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl2 at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm Vibrio growth within‐ and between‐species. This study showed that temperature and pH factors significantly affect Vibrio planktonic growth rates and V. parahaemolyticus biofilm formation. Therefore, pH effects must be added to the Vibrio growth modeling efforts to better predict Vibrio risk in estuarine and coastal zones that can potentially experience the cooccurrence of Vibrio and harmful algal bloom outbreak events. Plain Language Summary: Changes in temperature, salinity, and pH are increasing Vibrio‐human interactions in coastal communities. Multiple efforts have been developed to predict Vibrio risk, mainly using temperature and salinity measurements. However, more comprehensive models are needed to help inform decision‐makers on how to better design policies and create public health awareness. This study looks at how temperature and pH could affect the growth of the potential human bacterial pathogens, V. vulnificus and V. parahaemolyticus. Vibrio strains were grown in triplicate at different temperatures in acidic, neutral, and alkaline conditions (different pH ranges). The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the MatLab Curve Fitting Toolbox. This study found different optimal conditions for free‐living and aggregated Vibrio growth within and between species. In addition, this study showed that temperature and pH factors significantly impact Vibrio growth. Overall, the pH effects must be added to the Vibrio growth modeling efforts to have a more comprehensive model and to better predict Vibrio risk in climate change scenarios. Key Points: Optimal growth conditions for Vibrio spp. depend on the life stage: planktonic or biofilm formationChanges in pH and temperature in coastal areas may lead to a higher Vibrio‐human interaction and influence adaptative responsespH effects must be included in Vibrio modeling efforts to predict Vibrio risk in zones with co‐occurrence of Vibrio and harmful algal blooms [ABSTRACT FROM AUTHOR]

Purple nonsulfur bacteria (PNSB) were investigated for their carotenoid production and anti‐vibrio activity against acute hepatopancreatic necrosis disease (AHPND)‐causing Vibrio parahaemolyticus. To test carotenoid production, selected strains were cultivated in basic isolation medium (BIM), glutamate acetate medium, G5 medium and artificial acetic acid wastewater (AAW) medium. From 144 PNSB, Rhodopseudomonas palustris KTSSG46 was selected to produce carotenoids under microaerobic light conditions in BIM. When the culture medium was optimized, strain KTSSG46 grown in BIM modified with l‐glutamate at 1 g/L more effectively inhibited AHPND‐causing V. parahaemolyticus strains than standard BIM with 1 g/L (NH4)2SO4. BIM was further modified with 1.23 g/L MgSO4·7H2O and carotenoid production increased 40.22%. Carotenoid production at day 2 by strain KTSSG46 grown in BIM modified with l‐glutamate at 1 and 1.23 g/L MgSO4·7H2O was the same as production in BIM modified with monosodium glutamate (MSG). Culture supernatants from all BIM formulations showed similar activity against the resistant AHPND strain SR2. Based on high‐performance liquid chromatography, carotenoids of strain KTSSG46 might be canthaxanthin. Grown in BIM modified with MSG, strain KTSSG46 could produce inexpensive carotenoids and release anti‐vibrio compounds that, applied as shrimp feed additive, would prevent AHPND strains. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is an important pathogen causing pandemic diseases in marine animals and brings about severe economic losses in aquaculture worldwide. The emergence of multi‐drug‐resistant V. parahaemolyticus and the prohibition of antibiotics both require the development of new therapeutic agents with alternative action. In this study, the effect of gallnut Galla chinensis water extract (GWE) on V. parahaemolyticus growth and virulence was investigated to determine the potential for its use in disease prevention and treatment in aquaculture. The minimum inhibitory concentration and minimum bactericidal concentration of GWE against V. parahaemolyticus were identified as 0.49 and 0.98 mg/mL, respectively. Membrane damage in V. parahaemolyticus was further verified through the increase of conductivity and leakage of nucleic acids and proteins. Moreover, GWE caused membrane invaginations and damage in V. parahaemolyticus as observed via scanning electron microscopy. After treatment with GWE, the biofilm formation and the activities of respiratory chain dehydrogenase, lactate dehydrogenase, and succinate dehydrogenase of V. parahaemolyticus were all significantly inhibited. These findings suggest that GWE has the potential to be developed as a supplemental agent to mitigate the infections caused by V. parahaemolyticus in aquaculture. [ABSTRACT FROM AUTHOR]

Natural plant extracts (NPEs) may offer an effective alternative to minimize the consequences caused by antibiotic resistance in the marine industry. In this study, the anti‐Vibrio parahaemolyticus activities of several antibiotics and NPEs alone and in combinations were evaluated. The results indicated that the best combination was the 1/4 minimum inhibitory concentration (MIC) oxytetracycline +1/4 MIC hawthorn extract with fractional inhibitory concentration of 0.50. As a result, the survival rate of Exopalaemon carinicauda challenged by V. parahaemolyticus was improved to 53.3 ± 4.7% (as compared to 23.3 ± 2.3% in control) because of exposure to the combination of oxytetracycline +1/4 MIC hawthorn extract. Furthermore, the combination of upregulated digestive enzyme activities (cellulose, lipase, and pepsin), Toll receptor expressions, and immune parameters (alkaline phosphatase, and lysozyme) improved tolerance of E. carinicauda to V. parahaemolyticus infection. The synergistic anti‐V. parahaemolyticus functions may be associated with improved digestibility and immunity of E. carinicauda. Therefore, as a supplementary therapy to inhibit V. parahaemolyticus, the combinations of NPEs + antibiotics will hold better application potential for reducing antibiotic dosage and resistance. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus (V. parahaemolyticus) is an important foodborne pathogen known to cause severe enteric disease. Thus, timely detection of V. parahaemolyticus in seafood is crucial to prevent food poisoning and reduce economic losses. Traditional lateral flow immunoassay strips (LFIS) required good labelling materials and pairing of two antibodies, which made them costly and difficult to manufacture. In this study, a label‐free and lac dye coloration‐based LFIS (LD‐LFIS) to detect trh+V. parahaemolyticus was developed for the first time. Lac dye was used to stain V. parahaemolyticus, and LFIS was used to detect stained bacteria. Dimethyl sulphoxide (DMSO) and simultaneous mordanting were chosen as the best solvent and the best staining method for lac dye. In addition, three mordants [KAl(SO4)2·12H2O, NH4Fe(SO4)2·12H2O, and AlCl3·6H2O] were selected to improve dyeing efficiency. The detection limit of LD‐LFIS was 3.9 × 105 CFU/ml when NH4Fe(SO4)2·12H2O was used as mordant. Feasibility of the LD‐LFIS method was verified by detecting trh+V. parahaemolyticus in true and spiked seafood samples. The method developed in this study is expected to reduce restrictions on labelling materials and pairing of two antibodies on LFIS, and proposes a novel idea for the rapid detection of V. parahaemolyticus in seafood. [ABSTRACT FROM AUTHOR]

Summary: Vibrio parahaemolyticus infection in humans is associated with raw oyster consumption. Evaluation of V. parahaemolyticus presence in oysters is of most interest because of the economic and public health issues that it represents. To explore V. parahaemolyticus accumulation and depuration in adult Crassostrea gigas, we developed a GFP‐tagged V. parahaemolyticus strain (IFVp201‐gfp+), as well as a rapid and efficient quantification method in C. gigas oysters haemolymph by flow cytometry. Impact of the life history of C. gigas on accumulation and depuration of V. parahaemolyticus IFVp201 was subsequently investigated. We found that naive oysters, i.e. grown in controlled facilities with UV treated seawater, accumulated significantly more IFVp201 than environmental oysters, i.e. grown in intertidal environment. We hypothesized that environmental oysters could have been immune primed, thus could limit V. parahaemolyticus accumulation. Meanwhile, both naive and environmental oysters had similar depuration rates. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a common foodborne pathogenic bacterium and drug‐resistant strains are now widespread. Phages led by drug‐resistant V. parahaemolyticus strains are promising means to decrease the pressure on public health. We isolated a V. parahaemolyticus‐specific bacteriophage F23s1 that was active at wide ranges of temperature (30–60°C) and pH (4–10). Phage F23s1 exhibited a specific host range; in that, only 13 of the 23 V. parahaemolyticus strains were lysed. F23s1 effectively inhibited the growth of V. parahaemolyticus strain F23 in shrimp at 25°C within 12 h at a multiplicity of infection of 1000. We sequenced the genome of phage F23s1 which comprised a 76,648‐bp DNA with 105 open reading frames (ORFs) and identified an endolysin gene ORF52 that was then cloned and successfully expressed in Escherichia coli. The recombinant ORF52 protein significantly decreased OD600 nm of V. parahaemolyticus F23 from 0.978 to 0.249 when used at 20 µmol/L within 60 min. The endolysin also showed lytic activity against a panel of 23 drug‐resistant V. parahaemolyticus and 12 Salmonella strains with a higher lytic ability for V. parahaemolyticus. The phage F23s1 and its endolysin will be useful for preventing and controlling V. parahaemolyticus in food safety. [ABSTRACT FROM AUTHOR]

Consumption of raw oysters, whether wild‐caught or aquacultured, may increase health risks for humans. Vibrio vulnificus and Vibrio parahaemolyticus are two potentially pathogenic bacteria that can be concentrated in oysters during filter feeding. As Vibrio abundance increases in coastal waters worldwide, ingesting raw oysters contaminated with V. vulnificus and V. parahaemolyticus can possibly result in human illness and death in susceptible individuals. Depuration is a postharvest processing method that maintains oyster viability while they filter clean salt water that either continuously flows through a holding tank or is recirculated and replenished periodically. This process can reduce endogenous bacteria, including coliforms, thus providing a safer, live oyster product for human consumption; however, depuration of Vibrios has presented challenges. When considering the difficulty of removing endogenous Vibrios in oysters, a more standardized framework of effective depuration parameters is needed. Understanding Vibrio ecology and its relation to certain depuration parameters could help optimize the process for the reduction of Vibrio. In the past, researchers have manipulated key depuration parameters like depuration processing time, water salinity, water temperature, and water flow rate and explored the use of processing additives to enhance disinfection in oysters. In summation, depuration processing from 4 to 6 days, low temperature, high salinity, and flowing water effectively reduced V. vulnificus and V. parahaemolyticus in live oysters. This review aims to emphasize trends among the results of these past works and provide suggestions for future oyster depuration studies. [ABSTRACT FROM AUTHOR]

Summary: The lactoferricin expressed in Bacillus subtilis is relatively low in yield, making it hard to apply in industrial settings. We constructed a six tandem repeat of lactoferricin cDNA driven by promoter PtrnQ. After transformation, two transformants P245 and P263 possessing a stable inheritance of plasmid and high expression of lactoferricin were selected. The bactericidal activities, 1 μl of aliquot of a total 5.5 ml of solution extracted from 5 ml of cultured P245 and P263, were equivalent to the efficacy of 238.25 and 322.7 ng of Ampicillin against Escherichia coli, respectively, and 366.4 and 452.52 ng of Ampicillin against Staphylococcus epidermidis respectively. These extracts were able to kill an Ampicillin‐resistant E. coli strain. The bactericidal activities of P245 and P263 equivalent to the efficacy of Tetracycline against Vibrio parahaemolyticus and V. alginolyticus were also determined. Moreover, the bactericidal activities of P245 and P263 were 168.04 and 249.94 ng of Ampicillin against Edwardsiella tarda, respectively, and 219.7 and 252.43 ng of Tetracycline against Streptococcus iniae respectively. Interestingly, the survival rate of E. tarda‐infected tilapia fry fed the P263 extract displayed a significantly greater than that of the fry‐fed control strain. Collectively, these B. subtilis transgenic strains are highly promising for use in animal husbandry during a disease outbreak. [ABSTRACT FROM AUTHOR]

Summary: Vibrio parahaemolyticus is a marine bacterium and causes opportunistic gastroenteritis in humans. Clinical strains of V. parahaemolyticus contain haemolysin and type III secretion systems (T3SS) that define their pathotype. A growing number of strains isolated recently from the environment have acquired these virulence genes constituting a pool of potential pathogens. This study used comparative genomics to identify genetic factors that delineate environmental and clinical V. parahaemolyticus population and understand the similarities and differences between the T3SS2 phylotypes. The comparative analysis revealed the presence of a cluster of genes belonging to bacterial cellulose synthesis (bcs) in isolates of environmental origin. This cluster, previously unreported in V. parahaemolyticus, exhibit significant similarity to that of Aliivibrio fischeri, and might dictate a potentially new mechanism of its environmental adaptation and persistence. The study also identified many genes predicted in silico to be T3SS effectors that are unique to T3SS2β of tdh−trh+ and tdh+trh+ pathotype and having no identifiable homologue in tdh+trh− T3SS2α. Overall, these findings highlight the importance of understanding the genes and strategies V. parahaemolyticus utilize for the myriad interactions with its hosts, either marine invertebrates or humans. [ABSTRACT FROM AUTHOR]

Enterocytozoon hepatopenaei (EHP) and Vibrio parahaemolyticus acute hepatopancreatic necrosis disease (VPAHPND) are two of the diseases that have frequently infected farmed shrimp in recent years, causing great economic losses to the shrimp industry worldwide. In this study, we established a sensitive and accurate duplex droplet digital PCR (ddPCR) method that can simultaneously detect and quantify the two pathogens simultaneously. The results showed that the ddPCR methods could detect EHP and VPAHPND specifically. The sensitivity levels of ddPCR for EHP and VPAHPND were 2.3 copies/μl and 4.6 copies/μl, respectively, which were 10‐fold higher than the sensitivity of the qPCR assay and showed good reproducibility. Twenty‐six suspected diseased shrimp samples were used for practical determination. For EHP, the detection rates of ddPCR and qPCR were 53.84% and 42.31%, respectively; for VPAHPND, the detection rates of ddPCR and qPCR were both 23.08%. The results indicated that the ddPCR method shows superiority for detection in samples with low viral loads, which will facilitate monitoring of the source and transmission of EHP and VPAHPND and will help control shrimp epidemic disease. [ABSTRACT FROM AUTHOR]

An emerging serotype O10:K4 of Vibrio parahaemolyticus has been predominantly isolated from outbreaks and sporadic cases in China. Herein, we report the first case of infection due to V. parahaemolyticus O10:K4 isolated from a hospitalized patient with acute diarrhea in Thailand. We sequenced the whole genome of the O10:K4 strain and compared it with those of the pandemic O3:K6 strain, O10:K4 strains in China, and other clinical and environmental strains. The results suggested that the O10:K4 strains are not a mere serotype variant diverged from the pandemic O3:K6 strain, confirming that the O10:K4 strain emergence has spread to Southeast Asia. [ABSTRACT FROM AUTHOR]

The effect of sunlight and salinities (10, 20, 39, and 60 psu) on the survival of Vibrio parahaemolyticus strains carrying either (thermostable direct hemolysin) tdh, the (thermostable related hemolysin) trh, and both or none of them were studied in water microcosms stabilized at 20°C using plate count agar and acridine orange direct viable count. All V. parahaemolyticus strains exposed to sunlight rapidly lose their culturability and evolve into a viable but non‐culturable state (VBNC). However, the tdh positive strains remain more culturable than the non‐virulent or trh positive strain but statically insignificant. At tested salinities, the survival time was higher at 10, 20, and 60 psu compared with that observed in seawater (39 psu). In seawater under dark condition, Vibrio strains remain culturable for up to 200 days with a significant difference between strains (p < 0.05). Furthermore, the non‐pathogenic strain survives longer than the virulent ones. At different salinities, a better adaptation is observed at 10 and 20 psu compared with 39 and 60 psu. Resuscitations essays performed on VBNC bacteria in a nutrient broth at 20°C and 37°C does not show any revivification. Practitioner Points: Effect of sunlight and salinities on the survival of V. parahaemolyticus in the marine environment.Resuscitation essay performed on viable but no cultivable bacteria.Microscope motility examines show that all strains exposed to sunlight remain motile after the loss of cultivability. [ABSTRACT FROM AUTHOR]

As a marine food‐borne pathogen, Vibrio parahaemolyticus (V. parahaemolyticus) can cause human gastrointestinal disorders and pose a serious threat to food safety and public health worldwide. Using a portable scanner, herein, a real‐time fluorescence saltatory rolling circle amplification (RF‐SRCA) has been established for the rapid detection of V. parahaemolyticus in seafood targeting toxR gene. The RF‐SRCA results could be effectively determined within 20–60 min via real‐time fluorescence curve. Significant specificity of RF‐SRCA was exhibited against 12 V. parahaemolyticus strains and 29 non‐V. parahaemolyticus strains. The sensitivity and detection limit of V. parahaemolyticus in artificially contaminated raw oyster by RF‐SRCA were 3.2 × 100 fg μL−1 and 2.3 × 100 CFU g−1, respectively. Compared with SRCA by electrophoresis, RF‐SRCA has higher sensitivity, lower detection limit, and avoids complicated electrophoresis. Compared with visual SRCA, the RF‐SRCA takes shorter time, provides more accurate results and can eliminate the risk of cross‐contamination. Moreover, 236 seafood samples were investigated for V. parahaemolyticus contamination, and the results showed 100% sensitivity, 95.88% specificity and 98.31% accuracy compared with the ISO method. Therefore, RF‐SRCA possesses great potential as an accurate, specific, sensitive, rapid and convenient molecular diagnostic method for V. parahaemolyticus detection from various seafoods. [ABSTRACT FROM AUTHOR]

Objective: On 1 December 2020, the Department of Disease Control of Thailand was notified of a cluster of food poisoning cases among participants at a church festival in Mae Ai district, Chiang Mai province. We conducted an outbreak investigation to confirm diagnosis, describe the epidemiological characteristics of the outbreak, identify possible sources of the outbreak and provide appropriate control measures. Methods: We reviewed medical records of the food poisoning cases from the health care centres. Active case finding was conducted among participants who had consumed food and water at the festival. An environmental survey was done in the village where the festival was held. A case‐control study was conducted to identify the source of the outbreak. Samples for laboratory analysis included rectal swabs and fresh stool specimens from the cases and food handlers, surface swabs of cooking equipment, food, water and ice samples. Results: Among 436 participants surveyed, 368 (84.4%) cases of food poisoning were identified. The most common clinical manifestation was abdominal pain (89.7%), followed by watery diarrhoea (45.7%), nausea (43.5%), vomiting (38.9%), fever (18.5%) and bloody diarrhoea (4.6%). None died in this outbreak. The case‐control study showed that mixed spicy seafood salad served in the festival was significantly associated with the disease by both univariable and multivariable analyses. However, the causative agent could not be identified. The environmental investigation suggested this seafood might have been undercooked. Conclusion: Clinical manifestations of the cases, incubation period and the suspected seafood salad suggested seafood‐related food poisoning. Grimontia hollisae, the organism causing illness similar to Vibrio parahaemolyticus and commonly undetectable in the laboratory with routine testing, might be the pathogen that caused this outbreak. G. hollisae should be in differential diagnosis and identified in seafood‐associated outbreaks. [ABSTRACT FROM AUTHOR]

Human‐pathogenic marine bacteria in the genus Vibrio proliferate rapidly in shellfish tissues when exposed to warm ambient air conditions, such as during intertidal exposure. However, it remains unclear whether intertidal‐cultured shellfish are inherently associated with elevated Vibrio concentrations. Here we spatially matched eastern oysters (Crassostrea virginica) held in subtidal and intertidal aquaculture systems at six experimental oyster farms along the mid‐Atlantic coast and tested whether intertidal aquaculture elevates concentrations of V. parahaemolyticus, the predominant species associated with seafood‐related gastroenteritis, as well as concentrations of V. parahaemolyticus carrying the tdh and/or trh genes associated with pathogenicity in humans. Across the sites and over time, we found only slight evidence for increasing V. parahaemolyticus concentrations with exposure to ambient air at low tide; however, tdh/trh+ V. parahaemolyticus increased about 1.5‐fold. We also found that total V. parahaemolyticus concentrations and concentrations of tdh/trh+ V. parahaemolyticus did not differ between intertidal‐ and subtidal‐cultured oysters when submerged at high tides. Any changes to V. parahaemolyticus concentrations within oyster tissues, including concentrations of tdh/trh+ V. parahaemolyticus, therefore diminish with the incoming tide. Our results collectively support the existing time‐to‐cooling restrictions that are in place in many state Vibrio control plans, which involve minimizing the amount of time harvested shellfish can be held prior to cooling or refrigeration, but oppose more austere measures such as restricting or prohibiting intertidal harvest entirely. [ABSTRACT FROM AUTHOR]

Summary: Vibrio spp. thrive in warm water and moderate salinity, and they are associated with aquatic invertebrates, notably crustaceans and zooplankton. At least 12 Vibrio spp. are known to cause infection in humans, and Vibrio cholerae is well documented as the etiological agent of pandemic cholera. Pathogenic non‐cholera Vibrio spp., e.g., Vibrio parahaemolyticus and Vibrio vulnificus, cause gastroenteritis, septicemia, and other extra‐intestinal infections. Incidence of vibriosis is rising globally, with evidence that anthropogenic factors, primarily emissions of carbon dioxide associated with atmospheric warming and more frequent and intense heatwaves, significantly influence environmental parameters, e.g., temperature, salinity, and nutrients, all of which can enhance growth of Vibrio spp. in aquatic ecosystems. It is not possible to eliminate Vibrio spp., as they are autochthonous to the aquatic environment and many play a critical role in carbon and nitrogen cycling. Risk prediction models provide an early warning that is essential for safeguarding public health. This is especially important for regions of the world vulnerable to infrastructure instability, including lack of 'water, sanitation, and hygiene' (WASH), and a less resilient infrastructure that is vulnerable to natural calamity, e.g., hurricanes, floods, and earthquakes, and/or social disruption and civil unrest, arising from war, coups, political crisis, and economic recession. Incorporating environmental, social, and behavioural parameters into such models allows improved prediction, particularly of cholera epidemics. We have reported that damage to WASH infrastructure, coupled with elevated air temperatures and followed by above average rainfall, promotes exposure of a population to contaminated water and increases the risk of an outbreak of cholera. Interestingly, global predictive risk models successful for cholera have the potential, with modification, to predict diseases caused by other clinically relevant Vibrio spp. In the research reported here, the focus was on environmental parameters associated with incidence and distribution of clinically relevant Vibrio spp. and their role in disease transmission. In addition, molecular methods designed for detection and enumeration proved useful for predictive modelling and are described, namely in the context of prediction of environmental conditions favourable to Vibrio spp., hence human health risk. [ABSTRACT FROM AUTHOR]

In this study, four genes encoding secondary acyltransferases of lipid A in Vibrio parahaemolyticus ATCC33846 were identified. When the four genes were overexpressed in Escherichia coli MLK1067 that which produces the penta‐acylated lipid A lacking the secondary acylation at the C3′ position, a C12:0 secondary acyl chain was added at the C3′ position of lipid A only in E. coli overexpressing VP_RS01045, but not VP_RS00880, VP_RS08405, or VP_RS12170. When the four genes were overexpressed in E. coli MKV15b that produces lipid IVA, a C12:0 secondary acyl chain was again added at the C3′ position in E. coli overexpressing VP_RS01045, but a C14:0 secondary acyl chain was added at the C2′ position of lipid A in E. coli overexpressing VP_RS00880, VP_RS08405, or VP_RS12170. The results indicate that four acyltransferases of lipid A are encoded by VP_RS01045, VP_RS00880, VP_RS08405, or VP_RS12170 in V. parahaemolyticus. The acyltransferase encoded by VP_RS01045 adds a C12:0 secondary acyl chain at the C3′ position of lipid A, whereas the acyltransferase encoded by VP_RS00880, VP_RS08405, or VP_RS12170 adds a C14:0 secondary acyl chain at the C2′ position of lipid A. This work contributes to understanding the biosynthetic pathway of lipid A in V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

The transcriptome and antibiotic resistance of Vibrio parahaemolyticus isolated from Penaeus vannamei cultured in seawater (strain HN1)and freshwater (strain SH1) ponds were studied at different salinity (2‰ and 20‰). At different salinity, 623 differentially expressed genes (DEGs) significantly upregulated and 1,559 DEGs significantly downregulated in SH1. In HN1, 466 DEGs significantly upregulated and 1,930 DEGs significantly downregulated, indicating high salinity can lead to the downregulation of most genes. In KEGG analysis, the expression of DEGs annotated to starch and sucrose metabolism pathway was higher at 2‰ salinity than at 20‰ salinity in HN1 and SH1, implying salinity affected bacterial growth mainly through this pathway. In the enrichment analysis of upregulated DEGs, two pathways (Valine, leucine, and isoleucine degradation, and Butanoate metabolism) were significantly enriched at different salinity. Antibiotic‐susceptibility test discovered that SH1 isolated from P. vannamei cultured in freshwater was resistant to multiple drugs, including kanamycin, gentamicin, medemycin, and azithromycin, at a salinity of 2‰, whereas at 20‰ salinity, SH1 was not resistant to the drugs. The HN1 strain isolated from P. vannamei cultured in mariculture was resistant to polymyxin B and clindamycin at 20‰ salinity. Whereas, HN1 was intermediately susceptible to these two antibiotics at 2‰ salinity. These results indicate that the drug resistance of bacteria was affected by salinity. Furthermore, beta‐lactam resistance was significantly enriched in SH1 at different salinity, and the inhibition zone of penicillin G was consistent with the results of a beta‐lactam resistance pathway. [ABSTRACT FROM AUTHOR]

Bacteria exhibit chemotaxis by controlling flagellar rotation to move toward preferred places or away from nonpreferred places. The change in rotation is triggered by the binding of the chemotaxis signaling protein CheY‐phosphate (CheY‐P) to the C‐ring in the flagellar motor. Some specific bacteria, including Vibrio spp. and Shewanella spp., have a single transmembrane protein called ZomB. ZomB is essential for controlling the flagellar rotational direction in Shewanella putrefaciens and Vibrio parahaemolyticus. In this study, we confirmed that the zomB deletion results only in the counterclockwise (CCW) rotation of the motor in Vibrio alginolyticus as previously reported in other bacteria. We found that ZomB is not required for a clockwise‐locked phenotype caused by mutations in fliG and fliM, and that ZomB is essential for CW rotation induced by overproduction of CheY‐P. Purified ZomB proteins form multimers, suggesting that ZomB may function as a homo‐oligomer. These observations imply that ZomB interacts with protein(s) involved in either flagellar motor rotation, chemotaxis, or both. We provide the evidence that ZomB is a new player in chemotaxis and is required for the rotational control in addition to CheY in Vibrio alginolyticus. [ABSTRACT FROM AUTHOR]

Certain foodborne diseases are associated with antibiotic resistance, a significant problem throughout the world. Silver nanoparticles (AgNPs) using industrial waste from Eucalyptus camaldulensis and sericin, a protein derived from Bombyx mori, were synthesised by a one‐step approach. Spherical‐shaped nanoparticles with the average size of 17.19 nm exhibited strong antioxidant activity. The minimum bactericidal concentrations against foodborne pathogens including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Klebsiella pneumoniae, Salmonella Typhimurium, Shigella sonnei, Vibrio cholerae and Vibrio parahaemolyticus were between 2.96 and 11.83 µg/mL. Killing against L. monocytogenes and E. coli O157:H7 was observed within 4 h. Treatment with AgNPs at 0.25 – 0.5 × MIC significantly reduced biofilm production in all isolates (P < 0.05). AgNPs significantly impeded adhesion to and invasion of human epithelial Caco‐2 cells by L. monocytogenes and E. coli O157:H7 (P < 0.05). Biocompatibility assessment of AgNPs with Caco‐2 and human red blood cells demonstrated no toxic effects. [ABSTRACT FROM AUTHOR]

Pathogens adapted to sub‐lethal acidic conditions could increase the virulence and survival ability under lethal conditions. In the aquaculture industry, feed acidifiers have been used to increase the growth of aquatic animals. However, there is limited study on the effects of acidic condition on the virulence and survival of pathogens in aquaculture. In this study, we investigated the survival ability of Vibrioparahaemolyticus at lethal acidic pH (4.0) after adapted the bacteria to sub‐lethal acidic pH (5.5) for 1 hr. Our results indicated that the adapted strain increased the survival ability at lethal acidic pH invoked by an inorganic (HCl) or organic (citric) acid. RNA‐sequencing (RNA‐seq) results revealed that 321 genes were differentially expressed at the sub‐lethal acidic pH including cadC, cadBA and groES/groEL relating to acid tolerance response (ATR), as well as genes relating to outer membrane, heat‐shock proteins, phosphotransferase system and flagella system. Quantitative real‐time polymerase chain reaction (qRT‐PCR) confirmed that cadC and cadBA were upregulated under sub‐lethal acidic conditions. The CadC protein could directly regulate the expression of cadBA to modulate the ATR in V. parahaemolyticus. RNA‐seq data also indicated that 113 genes in the CadC‐dependent way and 208 genes in the CadC‐independent way were differentially expressed, which were related to the regulation of ATR. Finally, the motility and cytotoxicity of the sub‐lethal acidic adapted wild type (WT) were significantly increased compared with the unadapted strain. Our results demonstrated that the dietary acidifiers may increase the virulence and survival of V. parahaemolyticus in aquaculture. [ABSTRACT FROM AUTHOR]