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Background: In the context of pathogen surveillance, it is crucial to ensure interoperability and harmonized data. Several surveillance systems are designed to compare bacteria and identify outbreak clusters based on core genome MultiLocus Sequence Typing (cgMLST). Among the different approaches available to generate bacterial cgMLST, our research used an assembly-based approach (chewBBACA tool). Methods: Simulations of short-read sequencing were conducted for 5 genomes of 27 pathogens of interest in animal, plant, and human health to evaluate the repeatability and reproducibility of cgMLST. Various quality parameters, such as read quality and depth of sequencing were applied, and several read simulations and genome assemblies were repeated using three tools: SPAdes, Unicycler and Shovill. In vitro sequencing were also used to evaluate assembly impact on cgMLST results, for six bacterial species: Bacillus thuringiensis, Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Vibrio parahaemolyticus and Xylella fastidiosa. Results: The results highlighted variability in cgMLST, which not only related to the assembly tools, but also induced by the intrinsic composition of the genomes themselves. This variability observed in simulated sequencing was further validated with real data for six of the bacterial pathogens studied. Conclusion: This highlights that the intrinsic genome composition affects assembly and resulting cgMLST profiles, and that variability in bioinformatics tools can induce a bias in cgMLST profiles. In conclusion, we propose that the completeness of cgMLST schemes should be considered when clustering strains. [ABSTRACT FROM AUTHOR]

The alarming global rise in antibiotic resistance, driven by the widespread overuse of traditional antibiotics, has created an urgent demand for new antimicrobial solutions. This study presents zinc oxide (ZnO) nanorods as a potential nano-antibiotic agent. ZnO nanorods, with a 2:3 aspect ratio, were synthesized using an efficient one-step hydrothermal method at a low temperature of 100°C, reducing the synthesis time to just 5 hours. The synthesized ZnO nanorods' morphology, structure, and composition were characterized using scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy. The potent antimicrobial activity of these nanorods against common bacterial strains such as Escherichia coli, Bacillus subtilis, and Vibrio parahaemolyticus was examined through optical density at 600 nm (OD600) measurements and inhibition zone analysis, demonstrating substantial inhibition of bacterial growth. In particular, at a concentration of 5 mg/mL, ZnO nanorods achieved a 96% reduction of B. subtilis bacteria in OD600 and an impressive 99.87% reduction in culturing assays within one day, showcasing bactericidal efficiency on par with tetracycline at 0.003 mg/mL. Furthermore, a predictive model of bacterial growth was developed and validated, providing insights into the time-dependent bactericidal efficiency of the synthesized nanorods. These results highlight the potential of ZnO-based composites as a promising solution to combat antibiotic resistance, paving the way for next-generation antimicrobial materials. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the supplementation of the probiotic Pseudoalteromonas piscicida 1Ub to the biofloc system as an ecofriendly strategy for protecting white shrimp (Penaeus vannamei) from Vibrio parahaemolyticus infection. Shrimp with an average body weight of (0.50 ± 0.09) g were reared in 30 glass jars with a working volume of 2.5 L at a density of 20 ind/L. Shrimp were reared for 5 d for each treatment, which included the biofloc system without and with 106 colony forming unit (CFU) per mL probiotic. The regular clear water system was used as control. All treatment groups were challenged with 103, 105, and 107 CFU/mL V. parahaemolyticus. For the negative control, shrimp were reared without V. parahaemolyticus. The results showed that the density of V. parahaemolyticus cocultured with P. piscicida 1Ub decreased and the density of V. parahaemolyticus in rearing water and shrimp body in the probiotic-treated group was lower than that in the control group (P < 0.05). The survival and immune response (total hemocyte count, phagocytic activity, respiratory burst, phenoloxidase, and superoxide dismutase) of shrimp in the probiotic group was higher than that in the positive control (P < 0.05). Moreover, supplementing the biofloc system with the probiotic could protect shrimp hepatopancreas from damage caused by V. parahaemolyticus, regardless of bacterial density. Thus, the supplementation of the probiotic P. piscicida 1Ub in the biofloc system could significantly protect and increase the resistance of shrimp to V. parahaemolyticus infection. [ABSTRACT FROM AUTHOR]

The bacterium Vibrio parahaemolyticus is ubiquitous in tropical and temperate waters throughout the world and causes infections in humans resulting from water exposure and from ingestion of contaminated raw or undercooked seafood, such as oysters. We describe a nationwide outbreak of enteric infections caused by Vibrio parahaemolyticus in Australia during September 2021-January 2022. A total of 268 persons were linked with the outbreak, 97% of whom reported consuming Australia-grown oysters. Cases were reported from all states and territories of Australia. The outbreak comprised 2 distinct strains of V. parahaemolyticus, sequence types 417 and 50. We traced oysters with V. parahaemolyticus proliferation back to a common growing region within the state of South Australia. The outbreak prompted a national recall of oysters and subsequent improvements in postharvest processing of the shellfish. [ABSTRACT FROM AUTHOR]

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]

Introduction: Fluctuations in water quality characteristics influence the productivity of blue crabs (Callinectes sapidus), and the risk of human exposure to pathogenic Vibrio species. Thus, this study assessed the prevalence of total and pathogenic/clinical markers of Vibrio parahaemolyticus and Vibrio vulnificus in blue crabs and seawater from the Maryland Coastal Bays (MCBs) and the correlation between Vibrio levels and physicochemical parameters. Methods: Three to five crabs and 1 L of seawater were collected monthly for 3 years (May 2018 to December 2020) from six sites within the MCBs. Hemolymph and crab tissue were extracted and pooled for each site. Extracted hemolymph, crab tissue, and seawater were analyzed for V. parahaemolyticus and V. vulnificus using the Most Probable Number (MPN) and real-time PCR methods. A one-way Analysis of Variance (ANOVA), correlations, and linear models were used to analyze the data. Akaike Information Criterion (AICc) was evaluated to determine the model that provides the best fit to the data relating to Vibrio concentrations and environmental factors. Results: Results suggested that environmental factors could influence the growth of Vibrio spp. Both V. parahaemolyticus and V. vulnificus were more prevalent during the warmer months than colder months. Vibrio was more prevalent in crab samples compared to seawater. Vibrio vulnificus concentrations in seawater and hemolymph were positively correlated with temperature (p = 0.0143 seawater) and pH (p = 0.006 hemolymph). A negative correlation was observed between the concentration of V. vulnificus in whole crab (tissue) and dissolved oxygen level (p = 0.0256). The concentration of V. parahaemolyticus in seawater was positively correlated with temperature (p = 0.009) and negatively correlated with dissolved oxygen (p = 0.012). Discussion: These results provide current information on the spatial and temporal distributions of Vibrio spp. in the MCBs that are useful for implementing more efficient processing and handling procedures of seafood products. [ABSTRACT FROM AUTHOR]

This study developed a postbiotic fermentation solution for fresh oyster preservation with the use of food waste soy whey. Lactiplantibacillus plantarum 299V was able to proliferate in soy whey within 24 h without any supplementation. Pacific oysters (Magallana gigas) were immersed in the postbiotic fermentation solution and stored at 4 °C for 12 days. Pathogenic bacteria Vibrio parahaemolyticus and Salmonella enterica introduced by bioaccumulation were suppressed to levels below the detection limit (<2 log CFU/g) within 4 days. The spoilage-related microbial parameters and chemical parameters were maintained at low levels across the 12 days. Sensory evaluation revealed that the product had a positive effect on most of the participants (>60%). Overall, the postbiotic fermentation solution reported in this study enhanced the shelf life and safety of oysters in a sustainable way and could also be recognized as an innovative probiotic vehicle with potential implications for human health promotion. [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]

Simple Summary: Acute hepatopancreatic necrosis disease (AHPND) is a plasmid-encoded PirA/B toxin mediated bacterial disease that causes significant economic losses to the global shrimp industry. Since the first AHPND outbreak of Penaeus vannamei cultures in Korea in 2016, AHPND-associated Vibrio parahaemolyticus (VpAHPND) is still considered a major threat to the Korean shrimp industry. Although several diagnostic methods have been developed against AHPND, several concerns have been raised about the misdiagnosis of the pathogen due to the transferability and mutation of the plasmid. In this study, we report the emergence of a natural mutant VpAHPND (pirA−, pirB+), which was isolated from cultured P. vannamei in Korea, and also provide its detailed genomic and pathological characteristics. Acute hepatopancreatic necrosis disease (AHPND) is one of the most important diseases in the global shrimp industry. The emergence of mutant AHPND-associated V. parahaemolyticus (VpAHPND) strains has raised concerns regarding potential misdiagnosis and unforeseen pathogenicity. In this study, we report the first emergence of a type II (pirA−, pirB+) natural mutant, VpAHPND (strain 20-082A3), isolated from cultured Penaeus vannamei in Korea. Phenotypic and genetic analyses revealed a close relationship between the mutant strain 20-082A3 and the virulent Korean VpAHPND strain 19-021-D1, which caused an outbreak in 2019. Detailed sequence analysis of AHPND-associated plasmids showed that plasmid pVp_20-082A3B in strain 20-082A3 was almost identical (>99.9%) to that of strain 19-021-D1. Moreover, strains 20-082A3 and 19-021-D1 exhibited the same multilocus sequence type (ST 413) and serotype (O1:Un-typeable K-serogroup), suggesting that the mutant strain is closely related to and may have originated from the virulent strain 19-021-D1. Similar to previous reports on the natural mutant VpAHPND, strain 20-082A3 did not induce AHPND-related symptoms or cause mortality in the shrimp bioassay. The emergence of a mutant strain which is almost identical to the virulent VpAHPND highlights the need for surveillance of the pathogen prevalent in Korea. Further investigations to elucidate the potential relationship between ST 413 and recent Korean VpAHPND isolates are needed. [ABSTRACT FROM AUTHOR]

Seven new oleanane- type triterpene saponins, lysimaponins A-G, were isolated from aerial parts of Lysimachia laxa Baudo. Their chemical structures have been elucidated by analysis of spectroscopic and chemical methods. All compounds were evaluated for their antibacterial effects against Microcystis aeruginosa, Vibrio parahaemolyticus, V. harveyi, V. vulinificus, V. cholerae , and V. alginolyticus. All compounds showed potent antibacterial activities against the cyanobacteria M. aeruginosa with IC50 values ranging from 14.4 ± 1.2 to 35.3 ± 2.2 µg/mL. Compounds 1, 2, 4 - 7 inhibited V. parahaemolyticus with MIC values ranging from 64 to 256 µg/mL. The results suggested that saponins from L. laxa could be potential anti-cyanobacteria agents. [ABSTRACT FROM AUTHOR]

Taura syndrome in shrimp, caused by Taura syndrome virus (TSV), is a disease listed by the World Organisation for Animal Health (OIE) that has been identified in five continents, causing serious economic losses in years. Due to the lack of specific drugs available to treat Taura syndrome, an effective TSV detection method is urgently needed to ensure pathogen prediction and disease control. In this study, we developed and evaluated an isothermal enzymatic recombinase amplification–based assay (TSV-ERA) that was able to diagnose TSV within 20 min at an optimal temperature of 42 °C. In the reaction system, the optimal concentrations of the primer and the probe were 500 nM and 120 nM, respectively. When the plasmid standards were used as a detection template, the check-out time of TSV-ERA was 12 min (21.76 ± 0.60 Ct), and the limit of detection (LOD) was 3.6 × 101 copies/µL. Compared to the sensitivity of the TSV detection method recommended by the OIE, TSV-ERA was equal to real-time PCR (qPCR) and higher than one-step PCR. This assay was highly specific for TSV and had no cross-reactivity with Enterocytozoon hepatopenaei (EHP), white spot syndrome virus (WSSV), Vibrio parahaemolyticus strain causing acute hepatopancreatic necrosis disease (VpAHPND), infectious hypodermal and hematopoietic necrosis virus (IHHNV), and the genomic DNA of specific pathogen-free (SPF) shrimp. Compared with the common detection methods, the TSV-ERA assay was able to shorten the detection time and decrease the detection temperature while sustaining accurate sensitivity. Based on these results, our TSV-ERA detection method is simple, rapid, and effective, and has great potential in the detection of TSV. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a newly discovered virus, Decapoda iridovirus 1 (DIV1) can cause a mortality rate of up to 100% in crustaceans, leading to huge economic losses. At present, there is no effective prevention and control measures for this disease. In the present study, the specific primers targeting highly conserved regions of MCP gene were designed, and then a quantitative real-time PCR method was established. The results indicate that DIV1 quantitative real-time PCR established has good specificity and does not cross react with other pathogens including white spot syndrome virus (WSSV), infectious subcutaneous and hematopoietic necrosis virus (IHHNV) and Vibrio parahaemolyticus induced acute hepatopancreatic necrosis disease (VpAHPND). The real-time PCR was capable of detecting DIV1 DNA at a minimum concentration of 10 copies/µL within 34 cycles. The method has good repeatability, with intra group and inter group coefficients of variation both less than 2%. Thirty-two clinical samples were assessed using both the real-time PCR and conventional PCR. The results shown real-time PCR we established are more sensitive than conventional PCR. In conclusion, this method has strong specificity, stable repeatability, and high sensitivity, providing technical support for clinical diagnosis, epidemiology investigation and monitoring of DIV1. [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]

Acute hepatopancreatic necrosis disease, which can cause 100% mortality, is one of the main threats to farming Litopenaeus vannamei. We identified seven strains of pathogenic bacteria from ponds with outbreaks of acute hepatopancreatic necrosis at a L. vannamei farm in Zhuhai, China. Among the seven bacteria strains, one strain was isolated from aquaculture water, two strains were isolated from hepatopancreas, and the other four strains were isolated from juvenile shrimp. The results of 16S rRNA sequencing and biochemical identification showed that all seven pathogenic bacteria were Vibrio parahaemolyticus and that they carried the pirA and pirB virulence genes. These bacteria showed ß-hemolysis with translucent rings, and six serotypes were identified. The regression infection results showed that the lethal rates of the three V. parahaemolyticus strains of serotypes O1:KUT and OUT:KUT to L. vannamei were significantly higher than those of the other serotypes. The three V. parahaemolyticus strains had the same growth characteristics, and they all entered the growth plateau at 4 h after inoculation. In addition, the pathogenicity of the three V. parahaemolyticus strains were similar. In the present study, V. parahaemolyticus was identified as one of the pathogenic bacteria causing acute hepatopancreatic necrosis of L. vannamei, and the O1:KUT and OUT:KUT serotypes may be the main pathogenic strains in Zhuhai. These results provided a foundation for the isolation, identification, and pathogenicity study of acute hepatopancreatic necrosis of L. vannamei, providing a reference for the prevention and control direction of L. vannamei disease. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to investigate the epidemiological and genomic characteristics of Vibrio parahaemolyticus (V. parahaemolyticus) isolates from outbreaks in Huzhou, China. Methods: This study aims to analyze the epidemiological data on V. parahaemolyticus outbreaks reported in Huzhou from 2019 to 2023. A total of 70 V. parahaemolyticus outbreak isolates were collected. The antibiotic resistance, serotypes, molecular typing, and genomic characteristics of these isolates were analyzed. Results: Most outbreaks of V. parahaemolyticus infection occurred in the summer, and the majority of outbreaks occurred in restaurants and rural banquets. High resistance rates were observed for ampicillin (AMP, 24.29%), followed by tetracycline (TET, 15.71%) and trimethoprim-sulfamethoxazole (SXT, 15.71%). The newly emerged serotype O10:K4 became dominant from 2021 to 2023, with most isolates belonging to ST3. The resistance gene blaCARB was frequently detected among these isolates. The pulsed-field gel electrophoresis (PFGE) and whole-genome single-nucleotide polymorphisms (wgSNPs) effectively differentiated the nine outbreaks. Conclusion: The newly emerged serotype O10:K4 became dominant from 2021 to 2023, with most isolates being ST3. PFGE and WGS technologies provided reliable methods for typing and identifying V. parahaemolyticus for outbreaks. [ABSTRACT FROM AUTHOR]

Edwardsiella tarda (E. tarda) can infect humans and a variety of animals, including fish, amphibians, reptiles, birds, and mammals. However, a more highly sensitive, specific, and repeatable test for its detection is lacking. The objective of this study was to develop a highly sensitive, specific, and repeatable droplet digital polymerase chain reaction (ddPCR)-based method for the quantitative detection of E. tarda. The gyrB gene was selected as the target gene, and primers and probe were designed and synthesized. Using E. tarda genomic DNA as templates, the reaction method was optimized to establish a linear relationship with realtime PCR detection methods. The sensitivity, specificity, and repeatability of the method were analyzed, and clinical samples were tested. When the primer and probe concentrations were 900 and 300 nM, respectively, and the annealing temperature was 57°C, the efficiency of the ddPCR amplification reaction was highest and the boundary between positive and negative droplet distribution was clearest. The sensitivity was high, with detection limit being as low as 0.56 copies·µL-1; additionally, and a good linear relationship (R² = 0.9962) between ddPCR and real-time PCR detection, within the range of 1-25,000 copies·µL-1, was evident. The repeatability was good, with a detection coefficient of variation of 2.74%. There was no cross-reactivity with 15 other common pathogenic microorganisms in aquatic animals (Streptococcus agalactiae, Streptococcus iniae, Streptococcus suis type 2, Nocardia seriolae, Vibrio parahaemolyticus, Aeromonas sobria, red sea bream iridovirus, decapod iridescent virus 1, enterocytozoon hepatopenaei, carp edema virus, Koi herpesvirus, goldfish hematopoietic necrosis virus, tilapia lake virus, viral nervous necrosis virus, or grass carp reovirus) in positive samples. Among the 48 clinical samples, including Bahaba taipingensis and its live food fish, pond water samples, and routine monitoring samples (Koi), 21 were positive for E. tarda, consistent with the bacterial isolation and identification results. The E. tarda ddPCR detection method has high specificity, sensitivity, and repeatability, can more accurately quantify E. tarda, and provides a useful reference for research related to this bacterium. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The underlying evolutionary mechanisms driving global expansions of pathogen strains are poorly understood. Vibrio parahaemolyticus is one of only two marine pathogens where variants have emerged in distinct climates globally. The success of a Vibrio parahaemolyticus clone (VpST3) in Latin America- the first spread identified outside its endemic region of tropical Asia- provided an invaluable opportunity to investigate mechanisms of VpST3 expansion into a distinct marine climate. A global collection of VpST3 isolates and novel Latin American isolates were used for evolutionary population genomics, pangenome analysis and combined with oceanic climate data. We found a VpST3 population (LatAm-VpST3) introduced in Latin America well before the emergence of this clone in India, previously considered the onset of the VpST3 epidemic. LatAm-VpST3 underwent successful adaptation to local conditions over its evolutionary divergence from Asian VpST3 isolates, to become dominant in Latin America. Selection signatures were found in genes providing resilience to the distinct marine climate. Core genome mutations and accessory gene presences that promoted survival over long dispersals or increased environmental fitness were associated with environmental conditions. These results provide novel insights into the global expansion of this successful V. parahaemolyticus clone into regions with different climate scenarios. Vibrio parahaemolyticus Sequence Type 3 was first reported in India and expanded globally to areas with distinct climates including Latin America. In this study, the authors investigate the evolutionary mechanisms driving emergence of the strain in Latin America using 280 publicly available genomes and 32 samples newly sequenced in this study. [ABSTRACT FROM AUTHOR]

Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including Escherichia coli, Campylobacter jejuni, Vibrio parahaemolyticus, Salmonella Enteritidis, Staphylococcus aureus, Clostridium perfringens, spores of Bacillus subtilis and Bacillus anthracis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and Enterobacteriaceae as indicators of river contamination, as well as E. coli added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable E. coli continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of E. coli to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and Al2O3, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a leading cause of human gastroenteritis associated with seafood consumption. The present study aimed to investigate the occurrence and risk assessment of V. parahaemolyticus isolated from live Indian black clams, sediment, and water samples collected from shellfish harvesting areas located along the south-west coast of India. Out of the total 72 samples collected, 55.6% revealed the presence of V. parahaemolyticus; the highest occurrence was observed in shellfish samples. The presence of tdh and trh virulence genes was screened by multiplex PCR. Virulence genes could be detected in 25.8% of the strains; 19.35% of them were trh positive and 3.2% were tdh positive, while 3.2% of strains exhibited the coexistence of both virulence genes. Antimicrobial resistance (AMR) determined by the disk diffusion method revealed that 87% of the strains were multiple drug resistant and exhibited 21 diverse resistance patterns. The overall multiple antibiotic resistance (MAR) index values ranged from 0 to 0.8. To the best of our knowledge, this is the first report to document the presence of pathogenic and multidrug-resistant V. parahaemolyticus in shellfish harvesting areas of the Indian sub-continent. The study reveals possible health hazards associated with consuming shellfish harvested from the study area. [ABSTRACT FROM AUTHOR]

Simple Summary: Acute hepatopancreatic necrosis disease (AHPND) is one of the most serious diseases, leading to massive levels of death in marine shrimp. To achieve sustainable prevention, molecular breeding is a promising approach that requires DNA markers for genetic selection. The aim of this study was to identify DNA markers associated with the AHPND-tolerant phenotype in Litopenaeus vannamei using DArT sequencing and a genome-wide association study. The post-larval shrimp were examined for infection with Vibrio parahaemolyticus, which causes AHPND (VpAHPND), and examined for AHPND susceptibility and tolerance. DNA markers were identified in 93 individuals, including single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels). We found a number of filtered SNPs and InDels, while only four SNPs and 17 InDels were significantly associated with the trait of AHPND tolerance. This information could be useful as a genetic tool for the selection of AHPND-tolerant shrimp. Shrimp aquaculture is facing a serious disease, acute hepatopancreatic necrosis disease (AHPND), caused by Vibrio paraheamolyticus (VpAPHND). For sustainable shrimp aquaculture, massive losses of shrimp infected with VpAPHND must be prevented. Research and selection of shrimp tolerant to VpAPHND infection is a sustainable approach to reducing the risk of AHPND. This study focused on the identification and development of potential DNA markers associated with AHPND using DArT sequencing (DArTSeq) and a genome-wide association study. Three populations of post-larval Litopenaeus vannamei were immersed in VpAPHND to collect susceptible (D) and tolerant (S) samples. The 45 D and 48 S shrimp had their genotypes analyzed using DArTSeq. A total of 108,983 SNPs and 17,212 InDels were obtained from the DArTseq data, while the biallelic 516 SNPs and 2293 InDels were finally filtered with PIC < 0.1, MAF < 0.05, and a call rate ≥ 80%. The filtered variants were analyzed for their association with AHPND tolerance. Although there were no significantly associated SNPs and InDels above the Bonferroni correction threshold, candidate variants, four SNPs and 17 InDels corresponding to p < 0.01, were provided for further validation of the AHPND tolerance trait. The candidate SNPs are located on an exon of the zinc finger protein 239-like gene, an intron of an uncharacterized gene, and in intergenic regions. Most of the candidate InDels are in the intergenic regions, with fewer in the intronic and exonic regions. This study provides information on SNPs and InDels for white shrimp. These markers will support the variant database of shrimp and be useful in shrimp aquaculture for breeding selection. [ABSTRACT FROM AUTHOR]

Food-borne Vibrio parahaemolyticus has global economic and public health concern. The frequent way for humans to contract these bacteria is through seafood. In this study, 350 samples were analysed for the presence of Vibrio parahaemolyticus. Of those, 40 samples were found positive for the bacteria. Ten different antibiotics were used to test the antibiotic sensitivity of these 40 isolates, and they exhibited variable susceptibility pattern. The isolates showed 100% resistance to penicillin G followed by 80% and 75% resistance to ampicillin and streptomycin, respectively. The isolates were highly sensitive to ciprofloxacin (97.5%), followed by trimethoprim (90%), gentamicin (90%), chloramphenicol (87.5%), amikacin (80%), tetracycline (65%) and cephalothin (65%). Of the 40 isolates, 45.0%, 22.5%, 5.0%, 7.5% isolates were found resistant to 3, 4, 5 and 6 antibiotics, respectively. Multiple antibiotic resistance (MAR) index value above 0.2 was shown by 80% of the isolates. The presence of MAR highlights the essential need to determine drug susceptibility and monitor antimicrobial resistance profiles. This is crucial for enhancing food safety and protecting public health. By identifying resistant strains, we can develop more effective treatment strategies and implement measures to control the spread of resistant pathogens, thus preserving antibiotic efficacy and ensuring public well-being. [ABSTRACT FROM AUTHOR]

L-amino acid oxidase (LAAO) is a kind of immune protease widely found in nature. In order to explore the gene sequence characteristics of LAAO (PmLAAO) and its expression changes after stimulation by Vibrio parahaemolyticus, the full-length cDNA of PmLAAO was cloned in this study. The length of its open reading frame (ORF) is 1767 bp, encoding a total of 588 amino acids, and has the structure domain of FAD-binding domain and amino acid oxidase (Amino_oxidase), which is a member of the amino acid oxidase family. The results of multiple sequence comparisons and phylogenetic trees showed that PmLAAO was closely related to bicrustacea, among which LAAO was the most similar to the Mytilus californianus. qRT-PCR results showed that PmLAAO was expressed in gill, mantle, adductor muscle, gonadal gland and digestive gland, with the highest expression level in gill tissue. After stimulation by Vp, the expression level of PmLAAO in gill tissue was significantly increased, and the expression level was the highest 48 h after stimulation. These results provide a reference for the functional activity of the novel immune protease LAAO in bivalve shellfish. [ABSTRACT FROM AUTHOR]

Aquatic mammals in Indonesia are officially protected. However, there is a lack of research on these mammals, particularly in relation to potential diseasecausing bacteria. A study was conducted in a conservation pond to address this gap, where swab samples were taken from the blowholes of aquatic mammals. The focus was on identifying bacteria that could potentially cause infectious diseases in these animals. The results revealed V. parahaemolyticus bacterial isolates, which showed a 98% similarity to the registered V. parahaemolyticus in NCBI. These bacterial isolates exhibited hemolysin properties and demonstrated resistance to trimethoprim, streptomycin, cephalothin, and penicillin antibiotics. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus, an important food-borne pathogens found to be associated with seafoods and marine environs. It has been a topic of debate for many decades that most pathogens are known to enter a viable but nonculturable (VBNC) state under cold temperature and nutrient limited conditions. The present study examined the time required for the induction of VBNC state and the revival strategies of both the endemic O3:K6 and O1:K25 sporadic strains of V. parahaemolyticus. The results revealed that V. parahaemolyticus survived even after 55 days of incubation in nutrient starved media such as phosphate buffered saline (PBS) and Coastal Water (CW) and could be recovered by temperature upshift method, and compared the resuscitation using Dulbecco’s Modified Eagle Medium (DMEM), sheep blood serum, chitin flakes with live Artemia salina, and the results suggests that chitin plays a significant role in regulating the VBNC state. It was also confirmed by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscope (SEM) analysis that VBNC cells can alter their morphology to coccoid forms in order to survive in most extreme nutrient limited environment. Further data on the promoting factors and the exact mechanism that resuscitate VBNC V. parahaemolyticus in cold natural environments and frozen foods are needed to perform a robust risk assessment. [ABSTRACT FROM AUTHOR]

Antibiotic resistance in shrimp farms has emerged as an extremely serious situation worldwide. The main aim of this study was to optimize the cultural conditions for producing new antibiotic agents from marine Streptomyces species. Streptomyces SK3 was isolated from marine sediment and was identified by its 16S rDNA as well as biochemical characteristics. This microbe produced the highest concentration of bioactive secondary metabolites (BSMs) when cultured in YM medium (YM/2). It produced the maximum total protein (41.8 ± 6.36 mg/ml) during the late lag phase period. The optimum incubation temperature was recorded at 30 °C; BSMs were not produced at ≤10 °C within an incubation period of 3–4 days. The suitable agitation speed was found to be 200 rpm with pH 7.00. The proper carbon, nitrogen, and trace elements supplementation consisted of starch, malt extract, calcium carbonate (CaCO3), and magnesium sulfate (MgSO4). The ethyl acetate extract was found to act strongly against three vibriosis pathogens, Vibrio harveyi, Vibrio parahaemolyticus, and Vibrio vunificus, as indicated by the inhibition zones at 34.5, 35.4, and 34.3 mm, respectively. The extract showed the strongest anti-V. harveyi activity, as indicated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.101 ± 0.02 and 0.610 ± 0.04 mg/ml, respectively. Basic chemical investigation of the crude extract using thin layer chromatography (TLC), bioautography, liquid chromatography tandem mass spectrometry (LC‒MS/MS), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (1H-NMR) revealed that the active components were the terpenoid and steroid groups of compounds. They showed carboxylic acid and ester functions in their molecules. [ABSTRACT FROM AUTHOR]

A novel vibriophage vB_VpaM_XM1 (XM1) was described in the present study. Morphological analysis revealed that phage XM1 had Myovirus morphology, with an oblate icosahedral head and a long contractile tail. The genome size of XM1 is 46,056 bp, with a G + C content of 42.51%, encoding 69 open reading frames (ORFs). Moreover, XM1 showed a narrow host range, only lysing Vibrio xuii LMG 21346 (T) JL2919, Vibrio parahaemolyticus 1.1997, and V. parahaemolyticus MCCC 1H00029 among the tested bacteria. One-step growth curves showed that XM1 has a 20-min latent period and a burst size of 398 plaque-forming units (PFU)/cell. In addition, XM1 exhibited broad pH, thermal, and salinity stability, as well as strong lytic activity, even at a multiplicity of infection (MOI) of 0.001. Multiple genome comparisons and phylogenetic analyses showed that phage XM1 is grouped in a clade with three other phages, including Vibrio phages Rostov 7, X29, and phi 2, and is distinct from all known viral families that have ratified by the standard genomic analysis of the International Committee on Taxonomy of Viruses (ICTV). Therefore, the above four phages might represent a new viral family, tentatively named Weiviridae. The broad physiological adaptability of phage XM1 and its high lytic activity and host specificity indicated that this novel phage is a good candidate for being used as a therapeutic bioagent against infections caused by certain V. parahaemolyticus strains. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is an important foodborne bacterium that causes severe gastroenteritis following the consumption of contaminated seafood. To identify V. parahaemolyticus and determine its pathogenicity, the U.S. Food and Drug Administration (FDA)'s Bacteriological Analytical Manual (BAM) recommends a multiplex polymerase chain reaction (PCR) protocol to simultaneously detect the species-specific thermolabile hemolysin (tlh) gene and the pathogenic thermostable-related hemolysin (trh) and thermostable-direct hemolysin (tdh) genes. However, this assay has shown two limitations: difficulty in separating the amplicons of the trh (486 bp) and tlh (450 bp) genes due to their highly similar sizes, and the weaker band exhibited by the tdh gene amplicon (270 bp). The present study aimed to improve the BAM's multiplex PCR assay by separating the three amplicons with similar intensity. A new primer set was applied for the tlh gene (369 bp) alongside the existing primers for the trh and tdh genes. The amplicons for the three genes were effectively separated by electrophoresis on a 2% tris-borate-EDTA (TBE) agarose gel within 45 min. Primer concentrations of 0.25 µM for three genes produced a significant amount of amplicons among various combinations of primer concentrations with 35 PCR cycles. This assay exhibited a detection limit of 10 pg of bacterial DNA, demonstrating its high sensitivity. It did not display amplicons from nine Vibrio species known to be human pathogens or from 18 well-documented foodborne pathogens. Therefore, the present multiplex PCR protocol could help overcome the limitations of existing assays and provide a more reliable method for detecting the three genes of V. parahaemolyticus. [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 aimed to evaluate the supplementation of the probiotic Pseudoalteromonas piscicida 1Ub to the biofloc system as an ecofriendly strategy for protecting white shrimp (Penaeus vannamei) from Vibrio parahaemolyticus infection. Shrimp with an average body weight of (0.50 ± 0.09) g were reared in 30 glass jars with a working volume of 2.5 L at a density of 20 ind/L. Shrimp were reared for 5 d for each treatment, which included the biofloc system without and with 106 colony forming unit (CFU) per mL probiotic. The regular clear water system was used as control. All treatment groups were challenged with 103, 105, and 107 CFU/mL V. parahaemolyticus. For the negative control, shrimp were reared without V. parahaemolyticus. The results showed that the density of V. parahaemolyticus cocultured with P. piscicida 1Ub decreased and the density of V. parahaemolyticus in rearing water and shrimp body in the probiotic-treated group was lower than that in the control group (P

The bacterium Vibrio parahaemolyticus is ubiquitous in tropical and temperate waters throughout the world and causes infections in humans resulting from water exposure and from ingestion of contaminated raw or undercooked seafood, such as oysters. We describe a nationwide outbreak of enteric infections caused by Vibrio parahaemolyticus in Australia during September 2021–January 2022. A total of 268 persons were linked with the outbreak, 97% of whom reported consuming Australia-grown oysters. Cases were reported from all states and territories of Australia. The outbreak comprised 2 distinct strains of V. parahaemolyticus, sequence types 417 and 50. We traced oysters with V. parahaemolyticus proliferation back to a common growing region within the state of South Australia. The outbreak prompted a national recall of oysters and subsequent improvements in postharvest processing of the shellfish.

To explore the extraction process of mycosporine amino acids (MAAs) and the antibacterial mechanism of Vibrio parahaemolyticus, the effects of liquid-solid ratio, extraction temperature and extraction time on the yield of MAAs were analyzed by single factor and response surface optimization tests, and MAAs were isolated and identified by silica gel column chromatography, HPLC and ESI-MS. The antibacterial mechanism of MAAs against Vibrio parahaemolyticus was analyzed by scanning and fluorescence microscopy to observe the leakage of intracellular nucleic acids and proteins, and DNA decomposition. The results showed that the optimal extraction parameters of MAAs of Ulva lactuca was liquid-solid ratio of 25 mL/g, extraction temperature of 40 ℃ and extraction time of 118 min, and the yield of MAAs was 179.34±3.91 mg/g. MAAs significantly destroyed the cell membrane of Vibrio parahaemolyticus, causing the leakage of nucleic acid and proteins, and promoting the breakdown of DNA in the bacteria. MAAs were isolated by silica gel column chromatography to obtain two fractions, and the fraction H2 was identified as shinorine, and the content in Ulva lactuca dry powder could reach 10.32 mg/g. This study provides a technical reference for the preparation of MAAs of Ulva lactuca and the biological control of Vibrio parahaemolyticus.

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Vibrio parahaemolyticus is associated with severe food-borne illness in humans as well as substantial financial setbacks in the fishing sector. To investigate the prevalence, pathogenicity, virulence, as well as the resistance patterns of V. parahaemolyticus retrieved from Oreochromis niloticus, 180 O. niloticus (moribund fish; n = 120 and apparently healthy; n = 60) were indiscriminately collected from Lake Manzala, Egypt. Consequently, the clinical inspection, necropsy finding, and bacteriological analysis were performed. All the retrieved isolates tested positive for the groEL species-specific gene. Herein, the prevalence of V. parahaemolyticus in the collected fish was 8.9% (16/180), whereas the liver was the organ most prominently affected. PCR revealed that the most prevalent virulence-determinant genes associated with V. parahaemolyticus were the toxR and tlh genes (100% for each), then tdh (73.3%) and trh (26.7%) genes. Furthermore, 40% (18/45) of isolated V. parahaemolyticus were extensively drug-resistant (XDR) to seven antimicrobial classes and have blaTEM, blaOXA, sul1, aadA, ermB, and tetA genes. Additionally, 17.8% (8/45) of the obtained V. parahaemolyticus were multidrug-resistant (MDR) to three antimicrobial classes and owned blaTEM, ermB, and aadA genes. The pathogenicity assay accentuated the correlation between cumulative mortality and the virulent characteristics exhibited by the inoculated strain. Definitely, 77% mortality was recorded within eight days in fish injected with a virulent V. parahaemolyticus strain. Briefly, this research accentuated the occurrence of XDR V. parahaemolyticus in fish specifying a public health concern. The emerging MDR and XDR V. parahaemolyticus frequently harbored toxR, tlh, and tdh virulence genes, and blaTEM, blaOXA, sul1, aadA, ermB, and tetA or tetB antimicrobial resistance genes. [ABSTRACT FROM AUTHOR]

The shrimp farming sector has faced significant hurdles due to acute hepatopancreatic necrosis disease (AHPND). In this study, an attempt was made to combine the enzymatic recombinase amplification (ERA) assay and CRISPR-Cas12a (ERA-Cas12a) for the rapid detection of AHPND. A set of crRNA and ssDNA with high sensitivity and good specificity was screened, and the best optimized one-tube system was obtained. Our additional analysis focused on the sensitivity and specificity of ERA-Cas12a, contrasting it with the established methodology of the World Organization for Animal Health (WOAH). The ERA-Cas12a could deliver the desired outcomes in under 40 min with a detection limit of 2 × 103 copies/µL and showed no interaction with white spot syndrome virus (WSSV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), Enterocytozoon hepatopenaei (EHP), Taura syndrome virus (TSV), covert mortality nodavirus (CMNV), and decapod iridescent virus 1 (DIV1). Our actual sample detection results showed that the ERA-Cas12a system has the advantage of being more intuitive and fast without losing too much sensitivity compared with the nested PCR and quantitative real-time PCR (qPCR). Moreover, the detection results could be directly observed under blue light irradiation. All these results indicate that ERA-Cas12a provides a rapid and specific diagnosis of AHPND, which could further reduce the dependence on the instrument and effectively reduce aerosol pollution. It could be helpful in the prevention of shrimp disease and in reducing the economic loss of shrimp aquaculture. [ABSTRACT FROM AUTHOR]

Sexual dimorphism is a common feature in all crustaceans. However, little information is available on the relationship between sex and disease resistance in Litopenaeus vannamei. This study aimed to evaluate the differences in innate immunity characteristics between male and female L. vannamei under stimulation with Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (VpAHPND) or lipopolysaccharide (LPS). We found that the survival rates of female shrimp were significantly higher than those of males during VpAHPND stimulation (P < 0.05). In transcriptome analysis, we discovered obvious differences in the pathways activated for immune and metabolic responses between male and female shrimp after VpAHPND stimulation. Genes associated with immunity were downregulated in the VM (male stimulation group) vs. BM (male control group) comparison, whereas they were upregulated in the VF (female stimulation group) vs. BF (female control group) comparison. Furthermore, the transcriptome results showed that changes in processes such as carbohydrate metabolism and amino acid metabolism were also different between females and males. After LPS stimulation, the contents of semi-granular cells (SGCs) significantly decreased while those of granular cells (GCs) significantly increased in male shrimp, while the number of hyaline cells (HCs) decreased in female shrimp. The phagocytosis rate of hemocytes in male shrimp significantly decreased, while the catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO), and glutathione S-transferase (GSH-ST) contents in the plasma of female shrimp were higher than those in males. These results collectively indicate that female shrimp have superior disease resistance compared to males, which provides an important reference for subsequent breeding efforts aimed at enhancing disease resistance in L. vannamei. [ABSTRACT FROM AUTHOR]

In order to enhance the photodynamic inactivation (PDI) effect of curcumin, a novel class of halogenated curcumin derivatives X-cur (X = F, Cl or Br) was synthesized and screened for its potential for PDI by ultraviolet-visible (UV-Vis) absorption and fluorescence spectroscopy, singlet oxygen (1O2) generation capacity and theoretical calculations of excited states. The results demonstrated that as the relative molecular mass of the nonmetallic heavy atom halogen increased, the spin-spin coupling effect was gradually strengthened, so the smallest energy level difference (ΔEst(S1-T3)) between singlet excited state (S1) and triplet excited state (T3) (0.140 eV) and the highest spin-orbit coupling value (0.642 262 cm-1) were observed in Br-cur. This finding suggested that Br-cur was most likely to undergo transition into triplet state through intersystem crossing. Furthermore, compared to curcumin and other halogenated curcumins, Br-cur exhibited the smallest energy level difference (3.260 eV) between its S1 and ground state (S0) . Due to the aforementioned factors, Br-cur was highly prone to photooxidation and had the highest 1O2 generation capacity. Br-cur had a PDI effect on Vibrio parahaemolyticus, a prevalent foodborne pathogen in aquatic products, which depended on its concentration and light exposure duration and was significantly higher than that of curcumin. Thus, Br-cur has great potential for application as a novel PDI agent.

Acute hepatopancreatic necrosis (AHPND) is a bacterial disease caused by Vibrio bacteria that severely affects the Pacific white shrimp farming industry. Since AHPND was first identified in China and Vietnam in 2010, it was subsequently identified in Malaysia (2011), Thailand (2012), Mexico (2013), the Philippines (2014), South Korea (2016), Bangladesh (2017), the United States (US) (2017), and Japan (2020). AHPND causes significant economic losses of more than 7 billion US＄ annually to the global shrimp farming industry. It has severely restricted the development of the global shrimp farming industry. Many studies have shown that the pathogens of AHPND are Vibrio spp., including V. parahaemolyticus, V. owensii, V. campbellii, V. harveyi, V. punensis, and V. anguillarum. The virulence of these pathogenic strains was derived from a 70 kb virulent plasmid (pVA1-type plasmid). The pVA1-type plasmid carries pirAB genes encoding the binary toxin pirAB homologous to the insecticidal protein of Photobacterium phosphoreum. The pVA1-type plasmid has been confirmed to carry a novel trb type Ⅳ secretion system (T4SS). Trb-T4SS can mediate the conjugative transfer of the pVA1-type plasmid at high cell density for interspecific horizontal transfer.The quorum sensing (QS) system is also known as the density-sensing system. In the surrounding environment, the QS system allows bacteria to regulate the expression of multiple genes by sensing changes in the concentration of autoinducer signaling molecules. At high cell density, high concentrations of autoinducer signaling molecules bind to receptor proteins to inhibit phosphorylation cascades and high cell density master regulator OpaR is normally expressed. OpaR is involved in the regulation of various biological processes, such as biofilm-forming ability, motility, and the expression of the type Ⅲ and type Ⅳ secretion systems. Reportedly, high concentrations of signaling molecules in the QS system regulate the expression of key genes of the T4SS to increase the conjugative transfer efficiency of drug-resistant plasmids. However, the regulation of the T4SS by opaR in AHPND is not yet reported.In this study, OpaR, the high cell density master regulator of the QS system in V. parahaemolyticus, was selected to explore the relationship between the QS system and T4SS expression, as well as the conjugative transfer of the pVA1-type plasmid. The V. parahaemolyticus 20130629002S01::cat (Vp2S01::cat) strain, a pathogenic strain of AHPND, was used as the starting strain. The opaR gene was replaced with the erythromycin resistance gene (ermB) by homologous recombination and electroporation. The opaR mutant strain (Vp2S01::catΔopaR) was successfully constructed. The effects of OpaR on Vp2S01::cat were explored by performing growth curve and motility assays.Vp2S01::cat and Vp2S01::catΔopaR were cultured continuously for approximately 24 h in a shaking bed at 28 ℃ and 180 r/min. OD600 was measured every 2 h to compare the difference in growth. The results showed that there were no significant differences in the growth curves for Vp2S01::cat and Vp2S01::catΔopaR. Biofilm-forming ability was detected using a crystal violet staining assay. The results showed that the biofilm-forming ability of Vp2S01::catΔopaR was significantly reduced. Growth zone diameter was recorded in 0.3% (swimming) LB agar plates at 28 ℃ for 8 h to analyze the difference in swimming ability. We found that the swimming ability of Vp2S01::catΔopaR increased significantly by 2.67 times compared with that of Vp2S01::cat. Growth zone diameter was recorded in 1.5% (swarming) LB agar plates at 28 ℃ for 12 h to analyze the difference in swarming ability. The results showed that there was no significant difference in swarming ability between Vp2S01::cat and Vp2S01::catΔopaR. However, Vp2S01::catΔopaR had more missing colonies. Using VcLMB29 as the receptor strain, the conjugative transfer efficiency of Vp2S01::cat and Vp2S01::catΔopaR was compared at different time points. We found that the conjugative transfer efficiency of Vp2S01::catΔopaR increased after 12 and 24 h. The conjugative transfer efficiency after 24 h was increased by a factor of 265.43. RNA of Vp2S01::cat and Vp2S01::catΔopaR was extracted after 24 h of conjugative transfer and reverse-transcribed into cDNA for real-time quantitative fluorescence PCR (RT-qPCR). GyrB was used as the reference gene. AphA-qRT, opaR-qRT, and T4SS-qRT primers were used for RT-qPCR. The relative expression levels of genes were calculated using the 2–ΔΔCt method. The results showed that the relative expression levels of T4SS in the Vp2S01::catΔopaR experimental group were significantly increased by 1.13–3.21 times and that the relative expression levels of the key conjugative transfer genes traF, trbE, and traG were significantly increased by 1.96, 1.92, and 3.21 times, respectively.In conclusion, the opaR gene does not affect the growth and swarming motility but does affect the biofilm-forming and swimming ability of Vp2S01::cat. The high cell density master regulator OpaR may affect the conjugative transfer efficiency of the virulent plasmid by regulating the expression levels of T4SS. This study provides fundamental data for analyzing the mechanism by which the QS system regulates the expression of T4SS and the conjugative transfer of the pVA1-type plasmid in AHPND pathogenic bacteria, offering technical support for the control of the horizontal transfer of the virulent plasmid in AHPND-causing bacteria.

The efficacy of Chromolaena odorata leaf flour components (CO) to increase the growth performance, non-specific immune activity, and resistance against Vibrio parahaemolyticus of whiteleg shrimp (Litopenaeus vannamei) culture was evaluated. To this purpose, whiteleg shrimp post larvae were fed on diets supplemented with 0 and a 1.5 g CO/kg diet for 45 days in a pond. After feeding trials, the shrimps were identified for their growth parameters, collected, and injected with V. parahaemolyticus, then their non-specific immune activity and resistance to V. parahaemolyticus was observed for 14 days. Findings showed that CO increased the average body weight (7.71 g, 37%), weight gain (7.69 g, 40%), and specific growth rate (13.23%/day, 5.7%) as compared to the control. In addition, CO supplementation also increases shrimp’s hematologic and immune activity (total hemocyte counts [6.8 × 107 CFU/mL, 242.9%], differential hemocyte counts [27%, 142.1%], and prophenoloxidase activity [0.085%, 566.7%]). Finally, shrimp resistance to V. parahaemolyticus infection also increased after CO supplementation, with survival rates of 73.33% as compared to 23.33% for the control. It suggests that C. odorata leaf flour component supplementation at an optimal dose in the diet may be an effective strategy to increase growth and resistance to bacterial disease with reduced mortality in shrimp farms.

In this study, a luxS-deleted mutant of Vibrio parahaemolyticus was successfully constructed by homologous recombination technology, and the growth capacity, 4,5-dihydroxy-2,3-pentanedione (DPD) production, biofilm formation, motility, drug susceptibility, extracellular protein-secreting capacity, and quorum sensing-related gene expression of the wild and mutant strains were compared to understand the effects of luxS gene deletion in the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus. The results showed that the deletion of the luxS gene did not affect the drug susceptibility or growth capacity of the strain. Compared with the wild-type strain, the DPD production and mobility of the mutant strain was significantly reduced, while the capacity of biofilm formation and extracellular protease secretion after 24 hours of incubation was significantly enhanced. The real-time polymerase chain reaction (PCR) results showed that the expression of the flagellar synthesis gene flgM significantly increased, while the expression of the hemolysin secretion-related gene toxS, the flagella synthesis gene flaA and the outer membrane protein gene ompW decreased significantly in the mutant strain. This study provides a basis for further research on the regulation mechanism of the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus, which will be helpful for the prevention and control of V. parahaemolyticus.

Abstract Purpose Vibrio parahaemolyticus is a leading seafood borne pathogen worldwide. The aim of this study was to decipher the response mechanism of V. parahaemolyticus isolates of clinical and aquatic animal origins to the hypoxic condition, which challenges the bacterial survival in the host and in the environment. Methods Growth profiles of V. parahaemolyticus isolates (n = 5) of clinical and aquatic animal origins were examined at different stress conditions (osmolality, acid, temperature, and O2 concentrations). Draft genomes of the V. parahaemolyticus isolates were determined using the Illumina sequencing technique. Comparative genomic analysis were performed to identify and validate the hypoxic tolerance-related genes. Results The V. parahaemolyticus isolates had an oxygen concentration-dependent growth mode, and the 10% O2 condition strongly inhibited the bacterial growth, when incubated in TSB medium (pH 8.5, 3% NaCl) at 37 °C. Unexpectedly, in marked contrast to the normal 21% O2 condition, the 10% O2 treatment for 24 h significantly increased biofilm formation of V. parahaemolyticus isolates (p

Vibrio parahaemolyticus is a food-borne pathogen, which is often isolated from various seafood products. In this study, two kinds of bacteriophages was isolated from the offshore sediments samples. The anti-phage mutant strain were obtained after seventeen rounds of co-culture of Vibrio parahaemolyticus and mixed bacteriophage, multigroup sequencing was carried out on spontaneous the anti-phage mutant strain and the wild-type strain. We used the Sanger sequencing to verify the accuracy of the mutation sites. Biolog GEN III MicroPlates were used to evaluate the metabolic capacity of wild-type strains and the anti-phage mutant strain. In this study, we found that with flaG gene (slight homology to N terminus of multiple flagellins) mutated, making the bacteriophage unable to absorb to the cell surface of the host. And, the growth competitiveness of the anti-phage mutant strain is lower than the wild-type strain. These results indicated that the fitness cost, including loss of the growth competitiveness, constitutes a barrier to the prevalence of these defense mechanisms. And the selection pressure on different anti-phage strategies depends on the trade-off between mortality imposed by bacteriophages and fitness cost of the defense strategy under the given environmental conditions. In conclusion, this study provides valuable insights into the phagehost interaction and phage resistance in Vibrio parahaemolyticus. Our study provided knowledge for the evolutionary adaption of bacteria against the bacteriophage, which could add more information to understand the phage resistance mechanism before applying in the industry. [ABSTRACT FROM AUTHOR]

Crayfish (Procambarus clarkii) are economically important freshwater crustaceans. With the growth of the crayfish industry, the associated foodsafety risks should be seriously considered. Although Vibrio parahaemolyticus is commonly recognized as a halophilic foodborne pathogen associated with seafood, it has been found to be a major pathogen in crayfish-associated food poisoning cases. In this study, the V. parahaemolyticus contamination level in crayfish production-sale chain was investigated using crayfish and environmental samples collected from crayfish farms and markets. Serious V. parahaemolyticus contamination (detection rate of 66%) was found in the entire crayfish production-sale chain, while the V. parahaemolyticus contamination level of the market samples was extremely high (detection rate of 92%). The V. parahaemolyticus detection rate of crayfish surface was similar to that of whole crayfish, indicating that crayfish surface was important for V. parahaemolyticus contamination. The simulation experiments of crayfish for sale being contaminated by different V. parahaemolyticus sources were performed. All the contamination sources, containing V. parahaemolyticus-positive tank, water, and crayfish, were found to be efficient to contaminate crayfish. The crayfish tank displayed the most significant contaminating role, while the water seemed to inhibit the V. parahaemolyticus contamination. The contamination extent of the crayfish increased with the number of V. parahaemolyticus cells the tank carried and the contact time of the crayfish and the tank, but decreased with the time that the crayfish were maintained in the water. It was also confirmed that the crayfish surface was more susceptible to V. parahaemolyticus contamination than the crayfish intestine. Furthermore, the adsorption of V. parahaemolyticus onto the crayfish shell was analyzed. Over 90% of the V. parahaemolyticus cells were adsorbed onto the crayfish shell in 6 h, indicating a significant adsorption effect between V. parahaemolyticus and the crayfish shell. In conclusion, within a water-free sale style, the fresh crayfish for sale in aquatic products markets uses its shell to capture V. parahaemolyticus cells from the V. parahaemolyticusabundant environments. The V. parahaemolyticus contamination in crayfish for sale exacerbates the crayfish-associated food-safety risk. This study sheds light on V. parahaemolyticus control and prevention in crayfish industry. [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 aim of this study was to investigate the prevalence of Vibrionaceae family in retail seafood products available in the Qidong market during the summer of 2023 and to characterize Vibrio parahaemolyticus isolates, given that this bacterium is the leading cause of seafood-associated food poisoning. We successfully isolated a total of 240 Vibrionaceae strains from a pool of 718 seafood samples. The breakdown of the isolates included 146 Photobacterium damselae, 59 V. parahaemolyticus, 18 V. campbellii, and 11 V. alginolyticus. Among these, P. damselae and V. parahaemolyticus were the predominant species, with respective prevalence rates of 20.3% and 8.2%. Interestingly, all 59 isolates of V. parahaemolyticus were identified as non-pathogenic. They demonstrated proficiency in swimming and swarming motility and were capable of forming biofilms across a range of temperatures. In terms of antibiotic resistance, the V. parahaemolyticus isolates showed high resistance to ampicillin, intermediate resistance to cefuroxime and cefazolin, and were sensitive to the other antibiotics evaluated. The findings of this study may offer valuable insights and theoretical support for enhancing seafood safety measures in Qidong City. [ABSTRACT FROM AUTHOR]

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Vibrio genus is a common pathogen in aquaculture and causes acute hepatopancreatic necrosis disease (AHPND) and massive mortality of shrimp. Many studies have suggested that a single functional ingredient such as plant extract or organic acid can reduce the dependence on antibiotics and promote the growth and immunity of aquatic animals. In this study, we evaluated the effects of a phytobiotic-based compound additive (Sanacore® GM, SNGM), which had a successful trajectory of commercial application in fish farming. However, its effects on the hepatopancreas health and intestinal microbiota of shrimp after Vibrio challenge have not been well evaluated. In the present study, Pacific white shrimp were fed diets with or without supplementation of SNGM, and the SNGM grades were 0-g/kg (CON), 3-g/kg (SNGM3), and 5-g/kg (SNGM5) diets. The feed trial lasted 60 days, after which a Vibrio parahaemolyticus challenge was performed. The results showed that compared to the CON group, both the SNGM3 and SNGM5 groups had a significantly higher weight gain and a lower feed conversion ratio as well as higher survival after Vibrio parahaemolyticus challenge. In the growth trial, the SNGM3 group had a significantly increased total protein, albumin concentration, and acid phosphatase activity in hemolymph compared to the CON group. In the challenge experiment, the SNGM3 and SNGM5 groups had increased albumin and glucose contents as well as the activities of phenoloxidase, lysozyme, alkaline phosphatase, and superoxide dismutase in hemolymph. Both the SNGM3 and SNGM5 groups had improved morphology of the hepatopancreas and intestine. The SNGM5 group had alleviated gut microbiota dysbiosis induced by Vibrio infection by increasing the potential probiotic bacterium abundance (Shewanella) and decreasing the potential pathogenic bacteria abundance (Vibrio, Photobacteriuma, Pseudoalteromonas, and Candidatus_Bacilloplasma). In conclusion, the dietary phytobiotic-based additive at 3-g/kg level increased the growth and Vibrio parahaemolyticus resistance of Pacific white shrimp by promoting immune-related enzyme activities and improving the morphological structure of the hepatopancreas and intestine and the intestinal microbiota composition. [ABSTRACT FROM AUTHOR]