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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]

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Abstract 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.

Marine bioprospecting is a dynamic research field that explores the oceans and their biodiversity as noteworthy sources of new bioactive compounds. Anthozoans are marine animals belonging to the Cnidaria phylum characterized by highly specialized mechanosensory cells used both for defence against predators and prey capture. Here, high concentration of cnidocysts have been isolated from the Mediterranean zoanthid coral Parazoanthus axinellae (Schmidt, 1862) and their antimicrobial potential has been investigated. The cnidocyst extract exerted significant antibacterial activity against some human pathogens capable of developing resistance to conventional antibiotics such as Streptococcus agalactiae and Coccus sp., and against several Vibrio species, including some microbial strains for humans and farmed fish, such as Vibrio alginolyticus, Vibrio anguillarum, Vibrio fischeri, Vibrio harveyi, and Vibrio vulnificus. Results have been discussed in light of both the ecological aspects and biotechnological value of the cnidocyst extract in the nutritional, nutraceutical, and pharmaceutical fields. [ABSTRACT FROM AUTHOR]

Marine bioprospecting is a dynamic research field that explores the oceans and their biodiversity as noteworthy sources of new bioactive compounds. Anthozoans are marine animals belonging to the Cnidaria phylum characterized by highly specialized mechanosensory cells used both for defence against predators and prey capture. Here, high concentration of cnidocysts have been isolated from the Mediterranean zoanthid coral Parazoanthus axinellae (Schmidt, 1862) and their antimicrobial potential has been investigated. The cnidocyst extract exerted significant antibacterial activity against some human pathogens capable of developing resistance to conventional antibiotics such as Streptococcus agalactiae and Coccus sp., and against several Vibrio species, including some microbial strains for humans and farmed fish, such as Vibrio alginolyticus, Vibrio anguillarum, Vibrio fischeri, Vibrio harveyi, and Vibrio vulnificus. Results have been discussed in light of both the ecological aspects and biotechnological value of the cnidocyst extract in the nutritional, nutraceutical, and pharmaceutical fields.

This study aimed to evaluate the effect of different forms of artificially salinized on the zootechnical performance, bacterial counts in shrimp gut, and proximate composition of Penaeus vannamei in the grow-out phase in a synbiotic system. Four treatments in triplicate using a completely randomized design were established: SD — seawater diluted, LCSM — low-cost salt mixture, CS — commercial salt mixture, and SW — seawater were evaluated during 60 days in experimental tanks with 416 shrimp m−3. The values of calcium, magnesium, and total hardness remained above 35, 90, and 400 mg L−1, respectively. The main ions tended to increase along the culture, especially potassium, which caused a reduction in the Na:K ratio, providing values below 10:1, adding to total alkalinity values below 100 mg CaCO3 L−1 that may have reduced survival in low salinity treatments. The different forms of artificially salinized did not influence the final weight and specific growth rate; however, yield, FCR and survival were lower in low-salinity as compared to seawater. There was no influence of the different forms of artificially salinized on TCBS and MYP bacterial count values, shrimp proximate composition, and microbial floc. Based on the results obtained, it can be concluded that to improve survival and FCR, it is necessary to adjust the Na:K ratio, as well as increase total alkalinity levels throughout the culture time to rear P. vannamei in higher stocking densities in artificially salinized low-salinity water. [ABSTRACT FROM AUTHOR]

The ability to acquire iron from the environment is often an important virulence factor for pathogenic bacteria and Vibrios are no exception to this. Vibrios are reported mainly from marine habitats and most of the species are pathogenic. Among those, the pathogenic vibrios eg. V cholerae, V. parahaemolyticus, V. vulnificus causes foodborne illnesses. Vibrios are capable of producing all different classes of siderophores like hydroxamate (aerobactin), catecholate (vibriobactin, fluvibactin), carboxylate (vibrioferrin), and amphiphilic (amphibactin). Every different species of vibrios are capable of utilizing some endogenous or xenosiderophores. Being Gram-negative bacteria, Vibrios import iron siderophore via TonB dependent transport system and unlike other Gamma proteobacteria these usually possess two or even three partially redundant TonB systems for iron siderophore transport. Other than selected few iron siderophores, most pathogenic Vibrios are known to be able to utilize heme as the sole iron source, while some species are capable of importing free iron from the environment. As per the present knowledge, the spectrum of iron compound transport and utilization in Vibrios is better understood than the siderophore biosynthetic capability of individual species.

Cholera, an ancient waterborne diarrheal disease, remains a threat to public health, especially when climate/weather processes, microbiological parameters, and sociological determinants intersect with population vulnerabilities of loss of access to safe drinking water and sanitation infrastructure. The ongoing war in Ukraine has either damaged or severely crippled civil infrastructure, following which the human population is at risk of health disasters. This editorial highlights a perspective on using predictive intelligence to combat potential (and perhaps impending) cholera outbreaks in various regions of Ukraine. Reliable and judicious use of existing earth observations inspired mathematical algorithms integrating heuristic understanding of microbiological, sociological, and weather parameters have the potential to save or reduce the disease burden. Plain Language Summary: Predictive intelligence using data for satellites, microbiology and sociology should be utilized to combat potential cholera outbreaks in war torn Ukraine. Key Points: The risk of cholera in Ukraine will become significant with the noteworthy presence of plankton in the coastal regions, along with anomalous warm air temperatures and heavy precipitationEarth observations inspired anticipatory decision‐making framework is needed for preventing infectious disease outbreaks such as cholera in human populationRegions such as Pakistan with massive flooding may experience similar risks and should be evaluated accordingly [ABSTRACT FROM AUTHOR]

El uso de bacterias benéficas contribuye a mejorar la salud de los camarones. El kéfir es un conglomerado probiótico conformado por un grupo de microorganismos que conviven en simbiosis, principalmente bacterias ácido-lácticas y levaduras. El objetivo del trabajo fue evaluar el efecto del kéfir de agua en la reducción de vibrios presentes en el cultivo de Penaeus vannamei. Se utilizó un total de ocho contenedores con 30 L de agua de mar, en los que se mantuvieron 15 juveniles con un peso promedio de 1,39 ± 0,03 g por tratamiento, con 6% de recambio diario del agua. Se prepararon cuatro dietas elaboradas con 75% kéfir y 25% productos extracelulares (T1); 50% kéfir y 50% productos extracelulares (T2); 50% kéfir deshidratado y 25% productos extracelulares (T3), y una dieta control solamente con alimento balanceado de 36% proteínas (TC). Se alimentó los camarones con los tratamientos antes mencionados por 10 d. Los resultados del efecto inhibitorio sobre los vibrios indicaron que los tres tratamientos fueron significativamente diferentes en relación al control. En cuanto a la salud de los camarones, los tratamientos con kéfir y sus productos extracelulares presentaron hepatopáncreas con grado 1 en contenido de lípido y mejor formación de túbulos con respecto al control (grado 3). Asimismo, en branquias los tratamientos mostraron grado 2 en formaciones necróticas mientras el control presentó grado 3. Se recomienda el uso de kéfir como un aditivo dietético para disminuir la carga bacteriana, particularmente de tipo vibrios en el cultivo de juveniles de P. vannamei.

Serum resistance is recognized as one of the most important pathogenic traits of bacterial pathogens, and no control measure is available. Based on our previous discovery that pathogenic Escherichia coli represses glycine, serine, and threonine metabolism to confer serum resistance and that the reactivation of this pathway by exogenous glycine could restore serum sensitivity, we further investigate the mechanism underlying the action of glycine in Vibrio alginolyticus. Thus, V. alginolyticus is treated with glycine, and the proteomic change is profiled with tandem mass tag-based quantitative proteomics. Compared to the control group, glycine treatment influences the expression of a total of 291 proteins. Among them, a trap-type mannitol/chloroaromatic compound transport system with periplasmic component, encoded by N646_0992, is the most significantly increased protein. In combination with the pathway enrichment analysis showing the altered fructose and mannitol metabolism, mannitol has emerged as a possible metabolite in enhancing the serum killing activity. To demonstrate this, exogenous mannitol reduces bacterial viability. This synergistic effect is further confirmed in a V. alginolyticus–Danio rerio infection model. Furthermore, the mechanism underlying mannitol-enabled serum killing is dependent on glycolysis and the pyruvate cycle that increases the deposition of complement components C3b and C5b-9 on the bacterial surface, whereas inhibiting glycolysis or the pyruvate cycle significantly weakened the synergistic effects and complement deposition. These data together suggest that mannitol is a potent metabolite in reversing the serum resistance of V. alginolyticus and has promising use in aquaculture.

Abstract Cholera, an ancient waterborne diarrheal disease, remains a threat to public health, especially when climate/weather processes, microbiological parameters, and sociological determinants intersect with population vulnerabilities of loss of access to safe drinking water and sanitation infrastructure. The ongoing war in Ukraine has either damaged or severely crippled civil infrastructure, following which the human population is at risk of health disasters. This editorial highlights a perspective on using predictive intelligence to combat potential (and perhaps impending) cholera outbreaks in various regions of Ukraine. Reliable and judicious use of existing earth observations inspired mathematical algorithms integrating heuristic understanding of microbiological, sociological, and weather parameters have the potential to save or reduce the disease burden.

The ability to acquire iron from the environment is often an important virulence factor for pathogenic bacteria and Vibrios are no exception to this. Vibrios are reported mainly from marine habitats and most of the species are pathogenic. Among those, the pathogenic vibrios eg. V cholerae, V. parahaemolyticus, V. vulnificus causes foodborne illnesses. Vibrios are capable of producing all different classes of siderophores like hydroxamate (aerobactin), catecholate (vibriobactin, fluvibactin), carboxylate (vibrioferrin), and amphiphilic (amphibactin). Every different species of vibrios are capable of utilizing some endogenous or xenosiderophores. Being Gram-negative bacteria, Vibrios import iron siderophore via TonB dependent transport system and unlike other Gamma proteobacteria these usually possess two or even three partially redundant TonB systems for iron siderophore transport. Other than selected few iron siderophores, most pathogenic Vibrios are known to be able to utilize heme as the sole iron source, while some species are capable of importing free iron from the environment. As per the present knowledge, the spectrum of iron compound transport and utilization in Vibrios is better understood than the siderophore biosynthetic capability of individual species. [ABSTRACT FROM AUTHOR]

Los patógenos bacterianos como los Vibrios son considerados unos de los principales microorganismos oportunista en el cultivo de camarón, ocasionan grandes pérdidas económicas a este sector, para ello diferentes productores han utilizado los antibióticos de manera incorrecta lo que ocasiona resistencia en las bacterias. Con estos antecedentes los extractos de planta se convierten en una alternativa para inhibir crecimiento bacteriano y además ayuda para la salud del animal y cuidado del medio ambiente en acuacultura. En esta investigación se evaluó 100 µl de los extractos alcohólicos de Tomillo (Thymus vulgaris), Guayaba (Psidium guajava) y Eucalipto (Eucalyptus melliodora) los mismos que fueron expuestos con el Vibrio por 24 horas, se deja incubar a 25°C y se observa halo de inhibición. En el agua se colocó una concentración de 4mL/ L por 24 horas y en el alimento 400 µl/gr durante 10 días para ver la disminución de la presencia de vibrios. Tanto en agua como en él hepatopáncreas se pudo observar disminución de vibrios usando los 3 tratamientos. Conclusión, los extractos alcohólicos de estas tres plantas podría ser utilizado como tratamiento profiláctico frente a la vibriosis en el cultivo de camarón.

Antibiotics are often used to treat severe Vibrio infections, with third-generation cephalosporins and tetracyclines combined or fluoroquinolones alone being recommended by the US Centers for Disease Control and Prevention. Increases in antibiotic resistance of both environmental and clinical vibrios are of concern; however, limited longitudinal data have been generated among environmental isolates to inform how resistance patterns may be changing over time. Hence, we evaluated long-term trends in antibiotic resistance of vibrios isolated from Chesapeake Bay waters (Maryland) across two 3-year sampling periods (2009-2012 and 2019-2022). Vibrio parahaemolyticus ( n = 134) and Vibrio vulnificus ( n = 94) t ox R-confirmed isolates were randomly selected from both sampling periods and tested for antimicrobial susceptibility against eight antibiotics using the Kirby-Bauer disk diffusion method. A high percentage (94%-96%) of V. parahaemolyticus isolates from both sampling periods were resistant to ampicillin and only 2%-6% of these isolates expressed intermediate resistance or resistance to third-generation cephalosporins, amikacin, tetracycline, and trimethoprim-sulfamethoxazole. Even lower percentages of resistant V. vulnificus isolates were observed and those were mostly recovered from 2009 to 2012, however, the presence of multiple virulence factors was observed. The frequency of multi-drug resistance was relatively low (6%-8%) but included resistance against antibiotics used to treat severe vibriosis in adults and children. All isolates were susceptible to ciprofloxacin, a fluoroquinolone, indicating its sustained efficacy as a first-line agent in the treatment of severe vibriosis. Overall, our data indicate that antibiotic resistance patterns among V. parahaemolyticus and V. vulnificus recovered from the lower Chesapeake Bay have remained relatively stable since 2009.IMPORTANCE Vibrio spp. have historically been susceptible to most clinically relevant antibiotics; however, resistance and intermediate-resistance have been increasingly recorded in both environmental and clinical isolates. Our data showed that while the percentage of multi-drug resistance and resistance to antibiotics was relatively low and stable across time, some Vibrio isolates displayed resistance and intermediate resistance to antibiotics typically used to treat severe vibriosis (e.g., third-generation cephalosporins, tetracyclines, sulfamethoxazole-trimethoprim, and aminoglycosides). Also, given the high case fatality rates observed with Vibrio vulnificus infections, the presence of multiple virulence factors in the tested isolates is concerning. Nevertheless, the continued susceptibility of all tested isolates against ciprofloxacin, a fluoroquinolone, is indicative of its use as an effective first-line treatment of severe Vibrio spp. infections stemming from exposure to Chesapeake Bay waters or contaminated seafood ingestion., Competing Interests: The authors declare no conflict of interest.

The demand for minimally processed vegetables (African salad) has increased partly due to its inclusion in ready-to-eat foods. Nevertheless, the associated risk of the presence of emergent foodborne pathogens, such as Vibrio parahaemolyticus might be underestimated. The present study was designed to isolate and characterize foodborne V. parahaemolyticus from minimally processed vegetables using culture-based methods and molecular approach. A total of 300 samples were examined from retail outlets between November 2018 and August 2019 from Southern Nigeria. The prevalence of vibrios from the overall samples based on the colonial proliferation of yellow, blue-green and/or green colonies on thiosulfate citrate bile salts sucrose agar was 74/300 (24.6%). An average of two green or blue-green colonies from respective plates was screened for V. parahaemolyticus using analytical profile index (API) 20 NE. Polymerase chain reaction further confirmed the identity of positive V. parahaemolyticus. The counts of V. parahaemolyticus ranged from 1.5 to 1,000 MPN/g. A total of 63 recovered V. parahaemolyticus were characterized further. The resistance profile of the isolates include ampicillin 57/63 (90.5%), cefotaxime 41/63 (65.1%), ceftazidime 30/63 (47.6%), amikacin 32/63 (50.8%), kanamycin 15/63 (23.8%), and oxytetracycline 16/63 (25.4%). The multiple antibiotic index ranged from 0–0.81. The formation of biofilm by the isolates revealed the following: strong formation 15/63 (23.8%), moderate formation 31/63 (49.2%), weak formation 12/63 (19.1%), and no formation 5/63 (7.9%). A total of 63/63 (100%), 9/63 (14.3%), and 20/63 (31.8%) of the isolates harbored the tox R gene, TDH-related hemolysin (trh) and thermostable direct hemolysin (tdh) determinants respectively. The isolates with O2 serogroup were most prevalent via PCR. Isolates that were resistant to tetracycline, kanamycin, and chloramphenicol possessed resistant genes. The presence of multidrug-resistant vibrios in the minimally processed vegetables constitutes a public health risk and thus necessitates continued surveillance.

The EU-water framework directive (WFD) focuses on nutrient reductions to return coastal waters to the good ecological status. As of today, many coastal waters have reached a steady state of insufficient water quality due to continuous external nutrient inputs and internal loadings. This study focuses first on the current environmental status of mesohaline inner coastal waters to illustrate their needs of internal measures to reach demanded nutrient reductions and secondly, if mussel cultivation can be a suitable strategy to improve water quality. Therefore, nitrogen, phosphorus, chlorophyll a, and Secchi depth of nine mesohaline inner coastal waters in north east Germany were analyzed from 1990 to 2018. Two pilot mussel farms were used to evaluate their effectiveness as a mitigation measure and to estimate potential environmental risks, including the interactions with pathogenic vibrio bacteria. Further, estimated production and mitigation potential were used to assess economic profitability based on the sale of small sized mussels for animal feed and a compensation for nutrient mitigation. The compensation costs were derived from nutrient removal costs of a waste water treatment plant (WWTP). Results show that currently all nine water bodies do not reach the nutrient thresholds demanded by the WFD. However, coastal waters differ in nutrient pollution, indicating that some can reach the desired threshold values if internal measures are applied. The mitigation potential of mussel cultivation depends on the amount of biomass that is cultivated and harvested. However, since mussel growth is closely coupled to the salinity level, mussel cultivation in low saline environments leads to lower biomass production and inevitably to larger cultivation areas. If 50% of the case study area Greifswald Bay was covered with mussel farms the resulting nitrogen reduction would increase Secchi depth by 7.8 cm. However, high chlorophyll a values can hamper clearance rates (

Antimicrobial resistance (AMR) is a growing threat to the human, and animal population, worldwide. The antimicrobials used across all the sectors eventually pollute the aquatic environment and transform it into a hot spot for the emergence and spread of AMR. The bacteria under the genera Vibrio being ubiquitous to aquatic environment include a few species which are pathogenic to humans and aquatic animals. Despite extensive reviews available on AMR in human, terrestrial animal sectors and environment, there is a dearth of summarized information on AMR in Vibrios in shrimp aquaculture environment. In comparison to the human, and terrestrial animal health sector, a methodology for determination of AMR in vibrios associated with aquatic animals is still in its nascent stages and needs harmonization. The present review is centred on the AMR status in vibrios of shrimp farming environment and recent advances in the detection of resistance and discusses methodologies for AMR determination in vibrios and possible mitigation measures to control AMR spread. [ABSTRACT FROM AUTHOR]

Coastal water quality assessment is important to maintain a healthy environment for various uses including fisheries and recreation. Microbial populations are used as biological indicators of contamination to monitor water quality and are considered by the government to be one of the critical features for issuing safety guidelines. Different bacterial groups (pathogenic, vibrio and faecal) from five major recreational beaches of Chennai, India, were monitored for the assessment of coastal water quality. Faecal coliforms (FC) were high at all the beaches, with up to 4.2 × 105 CFU/mL and exceeding the normal standard limits of 100 CFU/100 mL set by the Central Pollution Control Board (CPCB) of India. Rainfall was found to have a role in the variability and distribution of indicator and pathogenic bacteria. The seasonal dry period witnessed elevated FC, while dilution in the wet period reduced Escherichia coli–like organisms (ECLO). High microbial counts were detected near the beach situated close to the river mouth, mainly due to discharges of untreated domestic sewage and industrial wastes. Similarly, the biological oxygen demand (BOD) was also high, 0.32 to 10.32 mg/L. Dissolved inorganic nitrogen (DIN) ranged from 2.21 to 134.53 μmol/L and inorganic phosphate (IP) ranged from 0 to 57.53 μmol/L. These values indicated the presence of significant untreated sewage in the coastal water. This study revealed that Chennai coastal waters carry high levels of faecal and pathogenic bacteria, detrimental for recreational and other contact activities. The quantitative and qualitative analyses will be useful for modelling and prediction of coastal water quality and management of other recreational beaches in India. [ABSTRACT FROM AUTHOR]

The demand for minimally processed vegetables (African salad) has increased partly due to its inclusion in ready-to-eat foods. Nevertheless, the associated risk of the presence of emergent foodborne pathogens, such as Vibrio parahaemolyticus might be underestimated. The present study was designed to isolate and characterize foodborne V. parahaemolyticus from minimally processed vegetables using culture-based methods and molecular approach. A total of 300 samples were examined from retail outlets between November 2018 and August 2019 from Southern Nigeria. The prevalence of vibrios from the overall samples based on the colonial proliferation of yellow, blue-green and/or green colonies on thiosulfate citrate bile salts sucrose agar was 74/300 (24.6%). An average of two green or blue-green colonies from respective plates was screened for V. parahaemolyticus using analytical profile index (API) 20 NE. Polymerase chain reaction further confirmed the identity of positive V. parahaemolyticus. The counts of V. parahaemolyticus ranged from 1.5 to 1,000 MPN/g. A total of 63 recovered V. parahaemolyticus were characterized further. The resistance profile of the isolates include ampicillin 57/63 (90.5%), cefotaxime 41/63 (65.1%), ceftazidime 30/63 (47.6%), amikacin 32/63 (50.8%), kanamycin 15/63 (23.8%), and oxytetracycline 16/63 (25.4%). The multiple antibiotic index ranged from 0–0.81. The formation of biofilm by the isolates revealed the following: strong formation 15/63 (23.8%), moderate formation 31/63 (49.2%), weak formation 12/63 (19.1%), and no formation 5/63 (7.9%). A total of 63/63 (100%), 9/63 (14.3%), and 20/63 (31.8%) of the isolates harbored the tox R gene, TDH-related hemolysin (trh) and thermostable direct hemolysin (tdh) determinants respectively. The isolates with O2 serogroup were most prevalent via PCR. Isolates that were resistant to tetracycline, kanamycin, and chloramphenicol possessed resistant genes. The presence of multidrug-resistant vibrios in the minimally processed vegetables constitutes a public health risk and thus necessitates continued surveillance. [ABSTRACT FROM AUTHOR]

The EU-water framework directive (WFD) focuses on nutrient reductions to return coastal waters to the good ecological status. As of today, many coastal waters have reached a steady state of insufficient water quality due to continuous external nutrient inputs and internal loadings. This study focuses first on the current environmental status of mesohaline inner coastal waters to illustrate their needs of internal measures to reach demanded nutrient reductions and secondly, if mussel cultivation can be a suitable strategy to improve water quality. Therefore, nitrogen, phosphorus, chlorophyll a, and Secchi depth of nine mesohaline inner coastal waters in north east Germany were analyzed from 1990 to 2018. Two pilot mussel farms were used to evaluate their effectiveness as a mitigation measure and to estimate potential environmental risks, including the interactions with pathogenic vibrio bacteria. Further, estimated production and mitigation potential were used to assess economic profitability based on the sale of small sized mussels for animal feed and a compensation for nutrient mitigation. The compensation costs were derived from nutrient removal costs of a waste water treatment plant (WWTP). Results show that currently all nine water bodies do not reach the nutrient thresholds demanded by the WFD. However, coastal waters differ in nutrient pollution, indicating that some can reach the desired threshold values if internal measures are applied. The mitigation potential of mussel cultivation depends on the amount of biomass that is cultivated and harvested. However, since mussel growth is closely coupled to the salinity level, mussel cultivation in low saline environments leads to lower biomass production and inevitably to larger cultivation areas. If 50% of the case study area Greifswald Bay was covered with mussel farms the resulting nitrogen reduction would increase Secchi depth by 7.8 cm. However, high chlorophyll a values can hamper clearance rates (<20 mg m-3 = 0.43 l h-1 dry weight g-1) and therefore the mitigation potential. Also, the risk of mussel stock loss due to high summer water temperatures might affect the mitigation potential. The pilot farms had no significant effect on the total organic content of sediments beneath. However, increased values of Vibrio spp. in bio deposits within the pilot farm (1.43 106 ± 1.10 106CFU 100 ml-1 (reference site: 1.04 106 ± 1.45 106 CFU 100 ml-1) were measured with sediment traps. Hence, mussel farms might act as a sink for Vibrio spp. in systems with already high vibrio concentrations. However, more research is required to investigate the risks of Vibrio occurrence coupled to mussel farming. The economic model showed that mussel cultivation in environments below 12 PSU cannot be economic at current market prices for small size mussels and compensations based on nutrient removal cost of WWTPs. [ABSTRACT FROM AUTHOR]

As plastic debris in the environment continues to increase, an emerging concern is the potential for microplastic to act as vectors for pathogen transport. With aquaculture the fastest growing food sector, and microplastic contamination of shellfish increasingly demonstrated, understanding any risk of pathogen transport associated with microplastic is important for this industry. However, there remains a lack of detailed, systematic studies assessing the interactions and potential impacts that the attachment of human and animal pathogens on microplastic may have. Here we synthesise current knowledge regarding these distinct microplastic-associated bacterial communities and microplastic uptake pathways into bivalves, and discuss whether they represent a human and animal health threat, highlighting the outstanding questions critical to our understanding of this potential risk to food safety. Microplastics are a major source of anthropogenic contamination in the oceans. This contamination is now widespread, recalcitrant, and likely to continue unabated into the future. Plastics represent an important environmental substrate for the colonisation of bacteria from the surrounding water column, with distinct communities, abundances, and population structures on the plastic surfaces. There is the potential for microplastics to act as a long-distance transport mechanism for human and animal pathogens, potentially spreading pathogenic bacteria into new areas. A variety of human pathogens have been found on microplastics in the open ocean, but we do not know their pathogenicity and virulence potential or what, if any, human pathogen transmission occurs via this route. There is increasing scientific consensus that microplastics may act as vectors for the spread of antimicrobial-resistance genes. [ABSTRACT FROM AUTHOR]

Although shrimp larvae are susceptible to many pathogens and water quality and diseases affect commercial shrimp production, the relation between these factors are less studied. Therefore, we aimed to investigate the effect of bacterial dynamics and water quality factors on Penaeus monodon larvae. We recorded the survival rates, water quality (total ammonia, nitrite, and nitrate concentration), heterotrophic bacteria, and vibrios during different P. monodon stages (nauplii, zoea, mysis stage, postlarvae). In ponds 1, 2, 3 and 4, the survival rates were significantly lower but the nitrite concentration and vibrio numbers (before mysis stage) were considerably higher than those in other ponds (P < 0.05), indicating that nitrite and vibrios influenced P. monodon survival during larva culture. Nitrite and nitrate concentrations increased from day 6, and increased dramatically by day 12. Total ammonia concentration increased continuously from day 1 to 15. Heterotrophic bacteria increased slowly in the nauplii and zoea stages, grew rapidly in the mysis stage, and remained almost stable and reduced slightly in postlarvae. In most ponds, vibrio numbers did not change significantly in the nauplii and zoea stages, but increased from the mysis stage and were >10-4 cfu/mL, which potentially cause shrimp disease. Therefore, we suggest that the mysis stage is the key time when water quality and bacteria increase rapidly, and precautions should be taken to improve water quality and inhibit vibrio growth. [ABSTRACT FROM AUTHOR]

Vibrios, which include more than 120 valid species, are an abundant and diverse group of bacteria in marine and estuarine environments. Some of these bacteria have been recognized as pathogens of both marine animals and humans, and therefore, their virulence mechanisms have attracted increasing attention. The type III secretion system (T3SS) is an important virulence determinant in many gram-negative bacteria, in which this system directly translocates variable effectors into the host cytosol for the manipulation of the cellular responses. In this study, the distribution of the T3SS gene cluster was first examined in 110 Vibrio strains of 26 different species, including 98 strains isolated from coastal areas in China. Several T3SS1 genes, but not T3SS2 genes (T3SS2α and T3SS2β), were universally detected in all the strains of four species, Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi, and Vibrio campbellii. The effector coding regions within the T3SS1 gene clusters from the T3SS1-positive strains were further analyzed, revealing that variations in the effectors of Vibrio T3SS1 were observed among the four Vibrio species, even between different strains in V. harveyi, according to their genetic organization. Importantly, Afp17, a potential novel effector that may exert a similar function as the known effector VopS in T3SS1-induced cell death, based on cytotoxicity assay results, was found in the effector coding region of the T3SS1 in some V. harveyi and V. campbellii strains. Finally, it was revealed that differences in T3SS1-mediated cytotoxicity were dependent not only on the variations in the effectors of Vibrio T3SS1 but also on the initial adhesion ability to host cells, which is another prerequisite condition. Altogether, our results contribute to the clarification of the diversity of T3SS1 effectors and a better understanding of the differences in cytotoxicity among Vibrio species.

Shrimp aquaculture industry comprises 15 % of the internationally traded seafood products targeted for human consumption. Diseases of shrimp have caused severe economic losses to the aquaculture industry. Among pathogenic bacteria, several Vibrio species known as shrimp pathogens are also human pathogens. This study was conducted to identify the incidence of diversified Vibrio species in the shrimp Penaeus monodon Fabricius, 1798 farms in Bangladesh. Different Vibrio selective media were used for primary isolation and 16S rRNA gene amplicons were sequenced, followed by phylogenetic analysis. The Vibrio strains were also tested against twelve antibiotics. Two strains V32 and V38 showed 99.93 % similarity with Vibrio azureus whereas V9 and V33 showed 100 % identity with Vibrio fluvialis. Comparison of 16S rRNA gene sequence of V37 with sequences from GenBank identified the strain as Vibrio xuii. The phylogenetic tree indicates that V24, V26, V34 and V35 are closely related with Vibrio parahaemolyticus. The strains V28 and V31 were identified as Vibrio vulnificus. One strain of Vibrio cholerae was also identified. Moreover, V22 was identified as Photobacterium damselae subsp. damselae, and V25 as Aeromonas hydrophila. Twelve strains of Vibrio were resistant to amoxycillin, whereas all 16 bacterial isolates showed sensitivity to nitrofurantoin, sulphamethoxazole, chloramphenicol, ciprofloxacin and tetracycline. Multidrug resistance was observed in three isolates viz. V28, V32 and V35 which were identified as V. vulnificus, V. azureus and V. parahaemolyticus, respectively having MAR index of 0.25. These findings might have potential applications in controlling shrimp and human pathogenic vibrios in the farming regions. [ABSTRACT FROM AUTHOR]

Vibrios, which include more than 120 valid species, are an abundant and diverse group of bacteria in marine and estuarine environments. Some of these bacteria have been recognized as pathogens of both marine animals and humans, and therefore, their virulence mechanisms have attracted increasing attention. The type III secretion system (T3SS) is an important virulence determinant in many gram-negative bacteria, in which this system directly translocates variable effectors into the host cytosol for the manipulation of the cellular responses. In this study, the distribution of the T3SS gene cluster was first examined in 110 Vibrio strains of 26 different species, including 98 strains isolated from coastal areas in China. Several T3SS1 genes, but not T3SS2 genes (T3SS2α and T3SS2β), were universally detected in all the strains of four species, Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi , and Vibrio campbellii. The effector coding regions within the T3SS1 gene clusters from the T3SS1-positive strains were further analyzed, revealing that variations in the effectors of Vibrio T3SS1 were observed among the four Vibrio species, even between different strains in V. harveyi , according to their genetic organization. Importantly, Afp17, a potential novel effector that may exert a similar function as the known effector VopS in T3SS1-induced cell death, based on cytotoxicity assay results, was found in the effector coding region of the T3SS1 in some V. harveyi and V. campbellii strains. Finally, it was revealed that differences in T3SS1-mediated cytotoxicity were dependent not only on the variations in the effectors of Vibrio T3SS1 but also on the initial adhesion ability to host cells, which is another prerequisite condition. Altogether, our results contribute to the clarification of the diversity of T3SS1 effectors and a better understanding of the differences in cytotoxicity among Vibrio species. [ABSTRACT FROM AUTHOR]

At present, AHPND continues to produce large losses in Mexican shrimp farms, but no scientific report on mortality in commercial hatcheries has been published. Here, we present the clinical signs, histopathological lesions, bacteriological analyses and identification through whole-genome sequencing of the isolates obtained in three natural outbreaks of AHPND in Penaeus vannamei postlarvae obtained from three local hatcheries. After three to four days of acclimation, mortality was recorded and clinical signs such as an empty digestive tract, whitish hepatopancreas, anorexia and lethargy were observed in shrimp postlarvae. Histopathological analysis and detection of pirAB genes using the PCR AP4 method after sample enrichment were used as presumptive diagnoses of AHPND. Significantly more Vibrio -like density (p = 0.045) and green colonies (p = 0.021) were found in the hepatopancreas of postlarvae affected by AHPND compared to apparently healthy organisms in outbreak 1 and 2, respectively. Finally, 29 isolates from the hepatopancreas and stomachs of shrimps with or without AHPND clinical signs were sequenced, and two new Vibrio species were obtained, one closely related to the Harveyi clade and one to the Orientalis clade. Vibrio campbellii were the most abundant species followed by V. parahaemolyticus. The six genomes identified as V. campbellii harbour the pVA1-like plasmid carrying the pirAB genes, responsible for producing the delta-endotoxin that causes AHPND. The pVA1-like plasmids were similar to V. parahaemolyticus strains from the Americas. pVA1 plasmid hosts the Tn3 transposon like the V. campbellii strain from Ecuador, but absent in the China strain, suggesting a horizontal plasmid transfer between coexisting V. parahaemolyticus and V. campbellii within a geographic region. These findings provided the first report of V. campbellii strains carrying a pVA1-like plasmid that causes AHPND in postlarvae from commercial hatcheries in Mexico and may help in the adoption of active genomic surveillance of this disease. • Apparent healthy shrimp postlarvae from hatcheries developed AHPND clinical signs after 72 to 96 h of transportation. • The clinical signs, histopathology and WGS identification of the isolates obtained in three outbreaks of AHPND are reported. • Two potential new species of Vibrio were identified and V. campbellii was the most abundant species harboring pVA1 plasmid. • This is the first report of V. campbellii strains carrying pirAB genes that cause AHPND in postlarvae in Mexico. [ABSTRACT FROM AUTHOR]

Marine Streptomyces sp. isolate S073 was shown to have strong antagonistic activity towards the pathogenic Vibrio parahaemolyticus using the agar diffusion method. The antagonistic substance(s) secreted into the supernatant was thermostable and non-proteinaceous in nature. S073 was found to produce carboxylate-type siderophores during most of its life cycle using a chrome azurol S assay. The antagonistic activity of S073 was mostly attributed to its higher ability to compete for iron compared with that of V. parahaemolyticus, as deduced from siderophore quantification. Iron supplementation studies indicated that additional mechanisms besides iron competition were simultaneously involved in governing the observed inhibition. Co-culture analysis indicated that S073, although disadvantaged in growth rate, was still competitive in inhibiting vibrios. The promising potential of S073 development as a biocontrol agent in aquaculture was discussed. [ABSTRACT FROM AUTHOR]

Abstract Shrimp cultivation has been faced with pathogenic bacterial infections, such as luminous vibriosis and acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio harveyi and Vibrio parahaemolyticus , respectively. Biodegradable compounds that act to prevent both serious shrimp diseases are to be explored for producing safe shrimp. The probiotic purple nonsulfur bacteria (PNSB) are safe for use in producing antivibrio compounds against shrimp pathogenic vibrios. The probiotic PNSB, Rhodobacter sphaeroides (SS15, TKW17) and Afifella marina STW181, released antivibrio compounds inhibiting various shrimp pathogenic Vibrio spp. in the optimum conditions that were similar to the conditions of shrimp cultivation. The antivibrio compounds by these PNSB were stable over the wide pH range from 3 to 10, and at elevated temperatures up to 121 °C for 20 min; they were also quite sensitive to lipase, pronase and α-chymotrypsin. All the antivibrio compounds had bactericidal activity as evidenced by damaged cells with many holes, and they also showed bacteriolytic activity with the highest found for the strain STW181. One of the purified antivibrio compounds produced by the strain SS15, a low molecular weight (<3000 Da) cationic compound containing NH 2 group(s), was the most effective in inhibiting AHPND-causing V. parahaemolyticus SR2. Regarding toxicity to brine shrimp, the extract from water layer in ethyl acetate extraction of strain SS15 (extract-SS15) containing antivibrio peptides had LC50 at 6.79 ± 0.63 mg mL−1. In challenge tests the extract-SS15 at 2.68 mg mL−1 adversely affected water quality; however, it could significantly decrease the mortality of white shrimp infected with the virulent AHPND strain SR2. All the tested probiotic PNSB produced antivibrio compounds that are biodegradable with great potential to control serious shrimp pathogenic vibrios for sustainable shrimp cultivation. Highlights • R. sphaeroides (SS15, TKW17) and A. marina STW181 released antivibrio compounds under the conditions of shrimp cultivation. • Antivibrio compounds of all tested probiotic strains were biodegradable but stable under wide ranges of pH and temperature. • The purified cationic compound with amino group(s) from strain SS15 strongly inhibited AHPND-causing V. parahaemolyticus SR2. • Effective dose of the extract-SS15 to control the virulent strain SR2 adversely affected water quality for rearing shrimp. [ABSTRACT FROM AUTHOR]

Abstract Globally, vibrios represent an important and well-established group of bacterial foodborne pathogens. The European Commission (EC) mandated the Comite de European Normalisation (CEN) to undertake work to provide validation data for 15 methods in microbiology to support EC legislation. As part of this mandated work programme, merging of ISO/TS 21872–1:2007, which specifies a horizontal method for the detection of V. parahaemolyticus and V. cholerae , and ISO/TS 21872–2:2007, a similar horizontal method for the detection of potentially pathogenic vibrios other than V. cholerae and V. parahaemolyticus was proposed. Both parts of ISO/TS 21872 utilized classical culture-based isolation techniques coupled with biochemical confirmation steps. The work also considered simplification of the biochemical confirmation steps. In addition, because of advances in molecular based methods for identification of human pathogenic Vibrio spp. classical and real-time PCR options were also included within the scope of the validation. These considerations formed the basis of a multi-laboratory validation study with the aim of improving the precision of this ISO technical specification and providing a single ISO standard method to enable detection of these important foodborne Vibrio spp.. To achieve this aim, an international validation study involving 13 laboratories from 9 countries in Europe was conducted in 2013. The results of this validation have enabled integration of the two existing technical specifications targeting the detection of the major foodborne Vibrio spp., simplification of the suite of recommended biochemical identification tests and the introduction of molecular procedures that provide both species level identification and discrimination of putatively pathogenic strains of V. parahaemolyticus by the determination of the presence of theromostable direct and direct related haemolysins. The method performance characteristics generated in this have been included in revised international standard, ISO 21872:2017, published in July 2017. [ABSTRACT FROM AUTHOR]

Microplastics (<5 mm) exhibit intrinsic features such as density, hydrophobic surface, or high surface/volume ratio, that are known to promote microbial colonization and biofilm formation in marine ecosystems. Yet, a relatively low number of studies have investigated the nature of microplastic associated bacterial communities in coastal ecosystems and the potential factors influencing their composition and structure. Here, we characterized microplastics collected in the Bay of Brest by manual sorting followed by Raman spectroscopy and studied their associated bacterial assemblages using 16S amplicon high-throughput sequencing. Our methodology allowed discriminating polymer type (polyethylene, polypropylene and polystyrene) within small size ranges (0.3–1 vs. 1–2 vs. 2–5 mm) of microplastics collected. Data showed high species richness and diversity on microplastics compared to surrounding seawater samples encompassing both free living and particle attached bacteria. Even though a high proportion of operational taxonomic units (OTU; 94 ± 4%) was shared among all plastic polymers, polystyrene fragments exhibited distinct bacterial assemblages as compared to polyethylene and polypropylene samples. No effect of microplastic size was revealed regardless of polymer type, site and date of collection. The Vibrio genus was commonly detected in the microplastic fraction and specific PCR were performed to determine the presence of potentially pathogenic Vibrio strains (namely V. aestuarianus and the V. splendidus polyphyletic group). V. splendidus related species harboring putative oyster pathogens were detected on most microplastic pools (77%) emphasizing the need of further research to understand the role of microplastics on pathogen population transport and ultimate disease emergence. [ABSTRACT FROM AUTHOR]

During summer 2014, a total of 89 Vibrio infections were reported in Sweden and Finland, substantially more yearly infections than previously have been reported in northern Europe. Infections were spread across most coastal counties of Sweden and Finland, but unusually, numerous infections were reported in subarctic regions; cases were reported as far north as 65°N, ≈100 miles (160 km) from the Arctic Circle. Most infections were caused by non-O1/O139 V. cholerae (70 cases, corresponding to 77% of the total, all strains were negative for the cholera toxin gene). An extreme heat wave in northern Scandinavia during summer 2014 led to unprecedented high sea surface temperatures, which appear to have been responsible for the emergence of Vibrio bacteria at these latitudes. The emergence of vibriosis in high-latitude regions requires improved diagnostic detection and clinical awareness of these emerging pathogens.

Antimicrobial resistance is a major public health concern restricted not only to healthcare settings but also to veterinary and environmental ones. In this study, we analyzed, by whole genome sequencing (WGS) the resistome, mobilome and virulome of 12 multidrug-resistant (MDR) marine strains belonging to Shewanellaceae and Vibrionaceae families collected at aquaculture centers in Italy. The results evidenced the presence of several resistance mechanisms including enzyme and efflux pump systems conferring resistance to beta-lactams, quinolones, tetracyclines, macrolides, polymyxins, chloramphenicol, fosfomycin, erythromycin, detergents and heavy metals. Mobilome analysis did not find circular elements but class I integrons, integrative and conjugative element (ICE) associated modules, prophages and different insertion sequence (IS) family transposases. These mobile genetic elements (MGEs) are usually present in other aquatic bacteria but also in Enterobacteriaceae suggesting their transferability among autochthonous and allochthonous bacteria of the resilient microbiota. Regarding the presence of virulence factors, hemolytic activity was detected both in the Shewanella algae and in Vibrio spp. strains. To conclude, these data indicate the role as a reservoir of resistance and virulence genes in the environment of the aquatic microbiota present in the examined Italian fish farms that potentially might be transferred to bacteria of medical interest.

The culture of red cusk eel Genypterus chilensis is currently considered a priority for Chilean aquaculture but low larval survival rates have prompted the need for the continuous use of antibacterials. The main aim of this study was to evaluate the role of live feed as a source of antibacterial-resistant bacteria in a commercial culture of G. chilensis. Samples of rotifer and Artemia cultures used as live feed were collected during the larval growth period and culturable bacterial counts were performed using a spread plate method. Rotifer and Artemia cultures exhibited high levels of resistant bacteria (8.03 × 104 to 1.79 × 107 CFU/g and 1.47 × 106 to 3.50 × 108 CFU/g, respectively). Sixty-five florfenicol-resistant isolates were identified as Vibrio (81.5%) and Pseudoalteromonas (15.4%) using 16S rRNA gene sequence analysis. A high incidence of resistance to streptomycin (93.8%), oxytetracycline (89.2%), co-trimoxazole (84.6%), and kanamycin (73.8%) was exhibited by resistant isolates. A high proportion of isolates (76.9%) carried the florfenicol-resistance encoding genes floR and fexA, as well as plasmid DNA (75.0%). The high prevalence of multiresistant bacteria in live feed increases the incidence of the resistant microbiota in reared fish larvae, thus proper monitoring and management strategies for live feed cultures appear to be a priority for preventing future therapy failures in fish larval cultures.

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This study was aimed to screen 22 purple nonsulfur bacteria (PNSB) isolates with the ability to secrete proteolytic enzymes and antivibrio compounds, including affecting factors on proteolytic enzyme production of the selected PNSB. Use of overlay diffusion method under aerobic dark conditions found that only 12 PNSB isolates (54.55%) were able to inhibit shrimp pathogenic Vibrio spp.; while 18 isolates (81.82%) could liquefy gelatin under conditions of aerobic dark and microaerobic light. Twenty-time freeze-dried culture supernatant concentrates collected from 12 PNSB grown under the microaerobic light conditions, with the use of agar well diffusion found that only strain PS342 was capable to inhibit all 6 tested shrimp pathogenic vibrios. Among 18 proteolytic PNSB, only 5 strains showed high activity of gelatin liquefaction and this included strain PS342. The strain PS342 was identified using 16 S rRNA gene as Rhodovulum sulfidophilum . Glutamate-malate (GM) medium supplemented with 1.5% NaCl was the most suitable medium by giving µ max as 0.336 h −1 . Use of central composite design, the maximal proteolytic activity was an average of 14.52 unit/ml in the suitable medium containing 1% gelatin under aerobic-dark conditions with the optimal speed at 150 rpm. The results of the verify test showed that optimum conditions (pH 7.90, 1.30% NaCl and 29.50 °C) for the proteolytic activity (15.40 unit/ml) were very close to real conditions for shrimp cultivation. R. sulfidophilum PS342 has the potential to be used in shrimp cultivation for its activities as a good producer of both proteolytic enzymes and antivibrio compounds. [ABSTRACT FROM AUTHOR]

Vibriosis is one of the important diseases causing economic loss to the shrimp industry worldwide. The present study reports field observations on the immune stimulatory effect of vibrio bacterin in commercial tiger shrimp ( Penaeus monodon) grow-out culture ponds ( n = 62) which were grouped under three stocking densities; low (6-8 nos per m2), medium (9-11 nos per m2) and high (12-14 nos per m2). The bacterin was administered in feed as a top dressing at final concentration equivalent to 2 × 108 CFU per kilogram feed twice a week throughout the culture period. In 20 representative ponds, total haemocyte count and prophenoloxidase activity in shrimp were significantly ( P < 0·05) higher and anatomical deformities like, antennae cut (5·02 ± 2·42), tail rot (5·10 ± 1·74), rostrum cut (4·49 ± 2·19) and soft shell (10·05 ± 5·77) were significantly lower compared to controls in all the studied stocking densities. Significant ( P < 0·05) improvement in production parameters like survival and production (kg ha1) was observed in all treatment ponds while similar improvement in average daily gain and feed conversion ratio could be observed in groups with low and medium stocking densities. Results of the study suggest that, oral administration of vibrio bacterin improves the immunity, reduces anatomical deformities and enhances the production in commercial shrimp culture operations. Significance and Impact of the Study Administration of vibrio bacterin in feed as a top dressing induced immune stimulation as indicated by higher levels of total haemocyte count and prophenoloxidase. Further reduction in percentage of animals with anatomical deformities suggests the protection against subclinical bacterial infections. The overall improvement in the production parameters like, average daily gain, survival, feed conversation ratio and production in different shrimp stocking densities under commercial farming conditions suggested the possible development of an immune stimulant product based on the inactivated vibrio bacteria for improved health and production in Penaeus monodon shrimp farming. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a Gram-negative bacterium found in marine and estuarine environments and is globally the leading cause of bacterial seafood-related illness. A real-time PCR assay for V. parahaemolyticus was developed for the marker toxR , with a large-scale and direct comparison of its applicability as a species-specific marker compared to the tlh gene carried out. Assays for tlh and toxR were used for 255 presumptive V. parahaemolyticus strains from our strain library, utilising both real-time ( toxR ) and conventional PCR assays ( tlh ). Of the 255 strains test, 254 results were in concordance; 255 strains were identified as being toxR positive (100%) and 254 strains were tlh positive (99.6%). The single discordant strain (isolate V12/023) was of interest, because it represented a presumptive V. parahaemolyticus strain, isolated from a clinical case. Whole genome sequence analysis and multi locus sequence typing of this single discordant strain was carried out, which unambiguously identified that the isolate was indeed V. parahaemolyticus. Genome analysis identified mismatches in the primer binding sites for the established tlh assay is likely responsible for the assay failing on this particular strain. The identification of false-negative results in strains that are implicated in human infections using the tlh assay and clearly highlights the relevance of the comparison with a toxR assay which showed 100% identification for the V. parahaemolyticus strains tested. [ABSTRACT FROM AUTHOR]

This study examined the effects of Bacillus licheniformis strain CIGBC-232, isolated from the gut of shrimp Litopenaeus vannamei and having antagonistic activity against Vibrio harveyi, on the immunity and larval quality of L. vannamei at various ontogenetic stages, in two separate experiments: (1) PL2 to PL17 exposed to the strain CIGBC-232 under laboratory conditions (2) zoea I to PL8 exposed to the strain CIGBC-232 and EPICIN 3W probiotics under farming conditions. The first experiment showed that phenoloxidase, peroxidase and superoxide dismutase activities were improved in animals grown with CIGBC-232 compared to the untreated control. In tests, the resistance to osmotic stress was also enhanced. During the second experiment, animals treated with CIGBC-232 exhibited significant ( P < 0.05) increases in phenoloxidase activity (30-40% higher in zoea I- II, mysis II- III and PL 2-7) and in the respiratory burst (30% higher from PL 2 to 7) as compared to those animals that received EPICIN 3W. There was no significant difference in the lectins and agglutinins (except in PL1, 6 and 7), in peroxidase and superoxide dismutase activities, in the resistance to osmotic stress, nor in the survival rate among treatments. CIGBC-232 treatment was able to reduce, the level of presumptive Vibrio spp. with respect to EPICIN 3W treatment in the tank water as well as in animals. At the end of both experiments, the growth of shrimp, i.e. weight and length was increased by CIGBC-232 treatment. This study showed the probiotic effect of CIGBC-232, which appeared to have a better probiotic performance than EPICIN 3W treatment. [ABSTRACT FROM AUTHOR]

Black band disease (BBD) of corals is a horizontally migrating, pathogenic, polymicrobial mat community which is active above a temperature threshold of 27.5°C on the reef. Bacterial isolates from BBD, the surface mucopolysaccharide layer (SML) of healthy corals and SML of healthy areas of BBD-infected corals were tested for production of short- to medium-chain acyl homoserine lactones (AHLs) using the Chromobacterium violaceum CV026 reporter strain. Of 110 bacterial isolates tested, 19 produced AHLs and 15 of these were from BBD. Eight AHLs were identified using LC-MS/MS, with 3OHC4 the most commonly produced, followed by C6. AHL-producing isolates exposed to three temperatures (24°C, 27°C, 30°C) revealed that production of three AHLs (3OHC4, 3OHC5 and 3OHC6) significantly increased at 30°C when compared to 24°C. 16S rRNA gene sequencing revealed that all of the AHL-producing BBD isolates were vibrios. Metagenomic data of BBD communities showed the presence of AHL (and autoinducer-2) genes, many of which are known to be associated with vibrios. These findings suggest that quorum sensing may be involved in BBD pathobiology and community structure due to enhanced production of quorum-sensing signal molecules (AHLs) above the temperature threshold of this globally distributed coral disease. [ABSTRACT FROM AUTHOR]

Microbial organisms can persist in the marine environment in a number of ways, for example during a free-living life stage or colonising the surface of plankton. These microorganisms include pathogens which may adversely impact the aquaculture and shellfishery sectors. Microbial diversity is well documented in nearshore bivalve culture environments, however, less is known about microbial communities in offshore environments. Additionally, oceanic fronts and currents may facilitate (or inhibit) planktonic dispersal, which can then allow for the movement of associated microbes across otherwise restrictive barriers. This study used zooplankton samples collected from the Irish and Celtic Seas to assess the zooplankton community structure and that of its associated microbial community. Zooplankton samples were identified using microscopy and screened using polymerase chain reaction (PCR) to identify pathogens with a potential aquaculture impact. Samples from four subareas representing the Irish Sea, Celtic Sea Front, Eastern Celtic Sea and Southern Celtic Sea also underwent sequencing of the bacterial V3–V4 region to define the bacteriome within these areas. All samples were dominated by crustaceans, and high molluscan numbers were evident around the Celtic Sea Front. There were distinct bacterial profiles, dominated by Cyanobacteria and Proteobacteria, and a positive relationship between Proteobacteria and copepods, chaetognaths and molluscs. A degree of connectivity was observed between the Eastern Celtic Sea and Celtic Sea Front, but the front acted as a barrier to the Irish Sea. The study also detected the bacterium Vibrio splendidus , potentially pathogenic to bivalves, and a low prevalence of a haplosporidian sequence detected in just one previous study to date. [Display omitted] • Zooplankton community structure was analysed across two dynamic shelf seas. • Microbial communities adhering to zooplankton were also characterised. • Oceanic currents and fronts facilitate or inhibit planktonic and microbial dispersal. • Bacteria and haplosporidia potentially pathogenic to cultured bivalves were detected. • Understanding dispersal enhances mitigation efforts when selecting culture sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Splendidus clade is predominant in oysters from central Chile. • Virulence is present in non-intensive farming environments. • Hemolytic activity was positive for 50% of the virulent strains. • Enzymes related to virulence are produced by the isolated vibrios. Farming intensification and climate change are inevitably linked to pathogen emergence in aquaculture. In this context, infectious diseases associated with vibrios span all developmental stages of the Pacific Oyster Crassostrea gigas. Moreover, virulence factors associated with pathogenicity spread among the vibrio community through horizontal gene transfer as part of the natural eco-evolutive dynamic of this group. Therefore, risk factors associated with the emergence of pathogens should be assessed before the appearance of mass mortalities in developing rearing areas. In this context, we characterized the vibrios community associated with oysters cultured in a non-intensive area free of massive mortalities located at Tongoy bay, Chile, through a culture-dependent approach. We taxonomically affiliated our isolates at the species level through the partial sequencing of the heat shock protein 60 gene and estimated their virulence potential through experimental infection of juvenile C. gigas. The vibrio community belonged almost entirely to the Splendidus clade, with Vibrio lentus being the most abundant species. The virulence potential of selected isolates was highly contrasted with oyster survival ranging between 100 and 30 %. Moreover, different vibrio species affected oyster survival at different rates, for instance V. splendidus TO2_12 produced most mortalities just 24 h after injection, while the V. lentus the most virulent strain TO6_11 produced sustained mortalities reaching 30 % of survival at day 4 after injection. Production of enzymes associated with pathogenicity was detected and hemolytic activity was positive for 50 % of the virulent strains and negative for 90 % of non-virulent strains, representing the phenotype that better relates to the virulence status of strains. Overall, results highlight that virulence is a trait present in the absence of disease expression, and therefore the monitoring of potentially pathogenic groups such as vibrios is essential to anticipate and manage oyster disease emergence in both established and under-development rearing areas. [ABSTRACT FROM AUTHOR]

Vibrio harveyi and related vibrios are potential pathogens causing luminous vibriosis in marine aquaculture systems. In this study, two lytic phages P4A and P4F isolated using Vibrio strains B4A and B4F as indicator bacteria, respectively, were isolated from seawater of an abalone farm. Vibrio strain B4F belongs to the Harveyi clade of the genus Vibrio and was found to cause mortality of abalones in laboratory microcosms. Both phages were able to lyse Vibrio strain B4F. Electron microscopy revealed that phage P4A had an icosahedral head while P4F possessed an elongated hexagonal head. Both phages belong to the family Siphoviridae with long non-contractile tails. Restriction endonuclease analysis indicated that both phages were double-stranded DNA viruses and the genome sizes of P4A and P4F were estimated to be about 49 and 44 kb respectively. One-step growth curves revealed that these two phages exhibited distinct latent periods, exponential periods and burst sizes by infecting the same Vibrio strain B4F. Both phages were able to significantly reduce Vibrio population density in biofilm formed by Vibrio strain B4F on the surface of polyethylene film. It is suggested that these two phages may be promising candidates as biocontrol agents of infections caused by Vibrio strains belonging to the Haveyi clade in marine aquaculture systems. [ABSTRACT FROM AUTHOR]

Coral reefs perform a major role in regulating marine biodiversity and serve as hotspot for highly dynamic and diverse microbiomes as holobionts. Corals around Ishigaki, however, are at risk due to tremendous stressors including elevation of seawater temperature, eutrophication and so on. However, no information is currently available on how Vibrio diversity fluctuates spatially and temporally due to environmental determinants in Ishigaki coral reef ecosystems. The aim of this study is to elucidate spatiotemporal Vibrio diversity dynamic at both community and population levels and to assess the environmental drivers correlated to Vibrio abundance and diversity. The Vibrio community identified based on pyrH gene phylogeny of 685 isolates from seawater directly connecting to Ishigaki coral holobionts consisted of 22 known and 12 potential novel Vibrionaceae species. The most prominent species were V. hyugaensis, V. owensii and V. harveyi followed by V. maritimus/V. variabillis, V. campbellii, V. coralliilyticus and P. rosenbergii. The Vibrio community fluctuations, assessed by PCoA with UniFrac distance and clustering with Euclidiean distance were varied less not only by year but also by site. Interestingly, significant positive correlation was observed between rising seawater temperature and the abundance of V. campbellii (r=0.62; P

Coral reefs perform a major role in regulating marine biodiversity and serve as hotspot for highly dynamic and diverse microbiomes as holobionts. Corals around Ishigaki, however, are at risk due to tremendous stressors including elevation of seawater temperature, eutrophication and so on. However, no information is currently available on how Vibrio diversity fluctuates spatially and temporally due to environmental determinants in Ishigaki coral reef ecosystems. The aim of this study is to elucidate spatiotemporal Vibrio diversity dynamic at both community and population levels and to assess the environmental drivers correlated to Vibrio abundance and diversity. The Vibrio community identified based on pyrH gene phylogeny of 685 isolates from seawater directly connecting to Ishigaki coral holobionts consisted of 22 known and 12 potential novel Vibrionaceae species. The most prominent species were V. hyugaensis, V. owensii and V. harveyi followed by V. maritimus/V. variabillis, V. campbellii, V. coralliilyticus, and Photobacterium rosenbergii. The Vibrio community fluctuations, assessed by PCoA with UniFrac distance and clustering with Euclidiean distance were varied less not only by year but also by site. Interestingly, significant positive correlation was observed between rising seawater temperature and the abundance of V. campbellii (r = 0.62; P < 0.05) whereas the opposite was observed for V. owensii (r = -0.58; P < 0.05) and the C6 group of V. hyugaensis (r = -0.62; P < 0.05). AdaptML-based microhabitat differentiation revealed that V. harveyi, V. campbellii, P. rosenbergii, and V. coralliilyticus populations were less-ecologically distinctive whereas V. astriarenae and V. ishigakensis were ecologically diverse. This knowledge could be important clue for the future actions of coral conservation. [ABSTRACT FROM AUTHOR]

Marine environmental conditions are naturally changing throughout the year, affecting life cycles of hosts as well as parasites. In particular, water temperature is positively correlated with the development of many parasites and pathogenic bacteria, increasing the risk of infection and diseases during summer. Interannual temperature fluctuations are likely to alter host–parasite interactions, which may result in profound impacts on sensitive ecosystems. In this context we investigated the parasite and bacterial Vibrionaceae communities of four common small fish species (three-spined stickleback Gasterosteus aculeatus , Atlantic herring Clupea harengus , European sprat Sprattus sprattus and lesser sand eel Ammodytes tobianus ) in the Northern Wadden Sea over a period of two years. Overall, we found significantly increased relative diversities of infectious species at higher temperature differentials. On the taxon-specific level some macroparasite species (trematodes, nematodes) showed a shift in infection peaks that followed the water temperatures of preceding months, whereas other parasite groups showed no effects of temperature differentials on infection parameters. Our results show that even subtle changes in seasonal temperatures may shift and modify the phenology of parasites as well as opportunistic pathogens that can have far reaching consequences for sensitive ecosystems. [ABSTRACT FROM AUTHOR]