Temporal and spatial distribution patterns of potentially pathogenic Vibrio spp. at recreational beaches of the German north sea

Occurrence, transmission and risks assessment of pathogens in aquatic environments accessible to humans

Pathogens are ubiquitously detected in various natural and engineered water systems, posing potential threats to public health. However, it remains unclear which human-accessible waters are hotspots for pathogens, how pathogens transmit to these waters, and what level of health risk associated with pathogens in these environments. This review collaboratively focuses and summarizes the contamination levels of pathogens on the 5 water systems accessible to humans (natural water, drinking water, recreational water, wastewater, and reclaimed water). Then, we showcase the pathways, influencing factors and simulation models of pathogens transmission and survival. Further, we compare the health risk levels of various pathogens through Quantitative Microbial Risk Assessment (QMRA), and assess the limitations of water-associated QMRA application. Pathogen levels in wastewater are consistently higher than in other water systems, with no significant variation for Cryptosporidium spp. among five water systems. Hydraulic conditions primarily govern the transmission of pathogens into human-accessible waters, while environmental factors such as temperature impact pathogens survival. The median and mean values of computed public health risk levels posed by pathogens consistently surpass safety thresholds, particularly in the context of recreational waters. Despite the highest pathogens levels found in wastewater, the calculated health risk is significantly lower than in other water systems. Except pathogens concentration, variables like the exposure mode, extent, and frequency are also crucial factors influencing the public health risk in water systems. This review shares valuable insights to the more accurate assessment and comprehensive management of public health risk in human-accessible water environments.

Vibrio alginolyticus growth kinetics and the metabolic effects of iron

IMPORTANCE

Transmission of V. alginolyticus occurs opportunistically through direct seawater exposure and is a function of its abundance in the environment. Like other Vibrio spp., V. alginolyticus are considered conditionally rare taxa in marine waters, with populations capable of forming large, short-lived blooms under specific environmental conditions, which remain poorly defined. Prior research has established the importance of temperature and salinity as the major determinants of Vibrio geographical and temporal range. However, bloom formation can be strongly influenced by other factors that may be more episodic and localized, such as changes in iron availability. Here we confirm the broad temperature and salinity tolerance of V. alginolyticus and demonstrate the importance of iron supplementation as a key factor for growth in the absence of thermal or osmotic stress. The results of this research highlight the importance of episodic iron input as a crucial metric to consider for the assessment of V. alginolyticus risk.

Environmental Factors Associated with Incidence and Distribution of V. parahaemolyticus and V. vulnificus in Chesapeake Bay, Maryland, USA: A three-year case study

Members of the genus Vibrio are ecologically significant bacteria native to aquatic ecosystems globally, and a few can cause diseases in humans. Vibrio-related illnesses have increased in recent years, primarily attributed to changing environmental conditions. Therefore, understanding the role of environmental factors in the occurrence and growth of pathogenic strains is crucial for public health. Water, oyster, and sediment samples were collected between 2009 and 2012 from Chester River and Tangier Sound sites in Chesapeake Bay, Maryland, USA, to investigate the relationship between water temperature, salinity, and chlorophyll with the incidence and distribution of Vibrio parahaemolyticus (VP) and Vibrio vulnificus (VV). Odds ratio analysis was used to determine association between the likelihood of VP and VV presence and these environmental variables. Results suggested that water temperature threshold of 20°C or higher was associated with an increased risk, favoring the incidence of Vibrio spp. A significant difference in salinity was observed between the two sampling sites, with distinct ranges showing high odds ratio for Vibrio incidence, especially in water and sediment, emphasizing the impact of salinity on VP and VV incidence and distribution. Notably, salinity between 9-20 PPT consistently favored the Vibrio incidence across all samples. Relationship between chlorophyll concentrations and VP and VV incidence varied depending on sample type. However, chlorophyll range of 0-10 μg/L was identified as critical in oyster samples for both vibrios. Analysis of odds ratios for water samples demonstrated consistent outcomes across all environmental parameters, indicating water samples offer a more reliable indicator of Vibrio spp. incidence.

First Steps towards a near Real-Time Modelling System of Vibrio vulnificus in the Baltic Sea

Over the last two decades, Vibrio vulnificus infections have emerged as an increasingly serious public health threat along the German Baltic coast. To manage related risks, near real-time (NRT) modelling of V. vulnificus quantities has often been proposed. Such models require spatially explicit input data, for example, from remote sensing or numerical model products. We tested if data from a hydrodynamic, a meteorological, and a biogeochemical model are suitable as input for an NRT model system by coupling it with field samples and assessing the models' ability to capture known ecological parameters of V. vulnificus. We also identify the most important predictors for V. vulnificus in the Baltic Sea by leveraging the St. Nicolas House Analysis. Using a 27-year time series of sea surface temperature, we have investigated trends of V. vulnificus season length, which pinpoint hotspots mainly in the east of our study region. Our results underline the importance of water temperature and salinity on V. vulnificus abundance but also highlight the potential of air temperature, oxygen, and precipitation to serve as predictors in a statistical model, albeit their relationship with V. vulnificus may not be causal. The evaluated models cannot be used in an NRT model system due to data availability constraints, but promising alternatives are presented. The results provide a valuable basis for a future NRT model for V. vulnificus in the Baltic Sea.

A systematic review, meta-analysis and meta-regression of the global prevalence of foodborne Vibrio spp. infection in fishes: A persistent public health concern

Human vibriosis, caused by pathogenic Vibrio spp., such as Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus, has been increasing worldwide, mediated by increasing consumption of seafood. The present study was conducted to examine the global prevalence of V. vulnificus, V. parahaemolyticus and V. cholerae in fishes. We searched PubMed, Web of Science, Scopus, and CNKI for peer-reviewed articles and dissertations prior to December 31, 2021. A total of 24,831 articles were retrieved, and 82 articles contained 61 fish families were included. The global pooled prevalence of V. cholerae, V. parahaemolyticus and V. vulnificus in fishes was 9.56 % (95 % CI: 2.12-20.92), 24.77 % (95 % CI: 17.40-32.93) and 5.29 % (95 % CI: 0.38-13.61), respectively. Subgroup and meta-regression analyses showed that study-level covariates, including temperature, country, continent, origin and detection methods partly explained the between-study heterogeneity. These heterogeneities were underpinned by differences of the three Vibrio spp. in fishes at geographical and climatic scales. These results reveal a high global prevalence of pathogenic Vibrio spp. in fishes and highlight the need for implementation of more effective prevention and control measures to reduce food-borne infection in humans.

Prevalence and Distribution of Potentially Human Pathogenic Vibrio spp. on German North and Baltic Sea Coasts

Global ocean warming results in an increase of infectious diseases including an elevated emergence of Vibrio spp. in Northern Europe. The European Centre for Disease Prevention and Control reported annual periods of high to very high risks of infection with Vibrio spp. during summer months along the North Sea and Baltic Sea coasts. Based on those facts, the risk of Vibrio infections associated with recreational bathing in European coastal waters increases. To obtain an overview of the seasonal and spatial distribution of potentially human pathogenic Vibrio spp. at German coasts, this study monitored V. cholerae, V. parahaemolyticus, and V. vulnificus at seven recreational bathing areas from 2017 to 2018, including the heat wave event in summer 2018. The study shows that all three Vibrio species occurred in water and sediment samples at all sampling sites. Temperature was shown to be the main driving factor of Vibrio abundance, whereas Vibrio community composition was mainly modulated by salinity. A species-specific rapid increase was observed at water temperatures above 10°C, reaching the highest detection numbers during the heat wave event with abundances of 4.5 log10 CFU+1/100 ml of seawater and 6.5 log10 CFU+1/100 g of sediment. Due to salinity, the dominant Vibrio species found in North Sea samples was V. parahaemolyticus, whereas V. vulnificus was predominantly detected in Baltic Sea samples. Most detections of V. cholerae were associated with estuarine samples from both seas. Vibrio spp. concentrations in sediments were up to three log higher compared to water samples, indicating that sediments are an important habitat for Vibrio spp. to persist in the environment. Antibiotic resistances were found against beta-lactam antibiotics (ampicillin 31%, cefazolin 36%, and oxacillin and penicillin 100%) and trimethoprim-sulfamethoxazole (45%). Moreover, isolates harboring pathogenicity-associated genes such as trh for V. parahaemolyticus as well as vcg, cap/wcv, and the 16S rRNA-type B variant for V. vulnificus were detected. All sampled V. cholerae isolates were identified as non-toxigenic non-O1/non-O139 serotypes. To sum up, increasing water temperatures at German North Sea and Baltic Sea coasts provoke elevated Vibrio numbers and encourage human recreational water activities, resulting in increased exposure rates. Owing to a moderate Baltic Sea salinity, the risk of V. vulnificus infections is of particular concern.

Epidemiological and microbiological investigation of a large increase in vibriosis, northern Europe, 2018

BackgroundVibriosis cases in Northern European countries and countries bordering the Baltic Sea increased during heatwaves in 2014 and 2018.AimWe describe the epidemiology of vibriosis and the genetic diversity of Vibrio spp. isolates from Norway, Sweden, Denmark, Finland, Poland and Estonia in 2018, a year with an exceptionally warm summer.MethodsIn a retrospective study, we analysed demographics, geographical distribution, seasonality, causative species and severity of non-travel-related vibriosis cases in 2018. Data sources included surveillance systems, national laboratory notification databases and/or nationwide surveys to public health microbiology laboratories. Moreover, we performed whole genome sequencing and multilocus sequence typing of available isolates from 2014 to 2018 to map their genetic diversity.ResultsIn 2018, we identified 445 non-travel-related vibriosis cases in the study countries, considerably more than the median of 126 cases between 2014 and 2017 (range: 87-272). The main reported mode of transmission was exposure to seawater. We observed a species-specific geographical disparity of vibriosis cases across the Nordic-Baltic region. Severe vibriosis was associated with infections caused by Vibrio vulnificus (adjOR: 17.2; 95% CI: 3.3-90.5) or Vibrio parahaemolyticus (adjOR: 2.1; 95% CI: 1.0-4.5), age ≥ 65 years (65-79 years: adjOR: 3.9; 95% CI: 1.7-8.7; ≥ 80 years: adjOR: 15.5; 95% CI: 4.4-54.3) or acquiring infections during summer (adjOR: 5.1; 95% CI: 2.4-10.9). Although phylogenetic analysis revealed diversity between Vibrio spp. isolates, two V. vulnificus clusters were identified.ConclusionShared sentinel surveillance for vibriosis during summer may be valuable to monitor this emerging public health issue.

Suspended particles are hotspots for pathogen-related bacteria and ARGs in coastal beach waters of northern China

Marine suspended particles are unique micro-habitats for diverse microbes and also hotspots of microbially metabolic activities. However, the association of bacterial pathogens, especially those carrying antibiotic resistance genes (ARGs), with these particles remain largely unknown in coastal habitats. This study investigated the distribution of pathogen-related bacteria and ARGs in particle-associated (PA) and free-living (FL) fractions of samples collected at three coastal beaches using NextGen sequencing and qPCR. Suspended particles were found to harbor significantly higher abundances of bacteria of pathogen-related genera and ARGs than their counterparts. Functional analysis of microbial community suggested that antibiotic biosynthetic pathways were also more abundant among PA microbiome comparing to FL microbial community, which further facilitated the spread of ARGs. Additionally, 13 pathogen-related genera co-occurred with ARG in PA fraction while only 2 pathogen-related genera co-occurred with ARGs in FL fraction. Overall, our research revealed suspended particles harbored more abundant pathogen-related genera and ARGs comparing with surrounding waters. Thus, suspended particles are hotspots for pathogen-related genera and ARGs and may pose a greater threat to human health in coastal beach.

Vibrio spp.: Life Strategies, Ecology, and Risks in a Changing Environment

Vibrios are ubiquitous bacteria in aquatic systems, especially marine ones, and belong to the Gammaproteobacteria class, the most diverse class of Gram-negative bacteria. The main objective of this review is to update the information regarding the ecology of Vibrio species, and contribute to the discussion of their potential risk in a changing environment. As heterotrophic organisms, Vibrio spp. live freely in aquatic environments, from marine depths to the surface of the water column, and frequently may be associated with micro- and macroalgae, invertebrates, and vertebrates such as fish, or live in symbiosis. Some Vibrio spp. are pathogenic to humans and animals, and there is evidence that infections caused by vibrios are increasing in the world. This rise may be related to global changes in human behavior (increases in tourism, maritime traffic, consumption of seafood, aquaculture production, water demand, pollution), and temperature. Most likely in the future, Vibrio spp. in water and in seafood will be monitored in order to safeguard human and animal health. Regulators of the microbiological quality of water (marine and freshwater) and food for human and animal consumption, professionals involved in marine and freshwater production chains, consumers and users of aquatic resources, and health professionals will be challenged to anticipate and mitigate new risks.

Improved isolation and detection of toxigenic Vibrio parahaemolyticus from coastal water in Saudi Arabia using immunomagnetic enrichment

Background

Vibrio parahaemolyticus is recognized globally as a cause of foodborne gastroenteritis and its widely disseminated in marine and coastal environment throughout the world. The main aim of this study was conducted to investigate the presence of toxigenic V. parahaemolyticus in costal water in the Eastern Province of Saudi Arabia by using immunomagnetic separation (IMS) in combination with chromogenic Vibrio agar medium and PCR targeting toxR gene of species level and virulence genes.

Methods

A total of 192 seawater samples were collected from five locations and enriched in alkaline peptone water (APW) broth. One-milliliter portion from enriched samples in APW were mixed with an immunomagnetic beads (IMB) coated with specific antibodies against V. parahaemolyticus polyvalent K antisera and separated beads with captured bacteria streaked on thiosulfate citrate bile salts sucrose (TCBS) agar and CHROMagar Vibrio (CaV) medium.

Results

Of the 192 examined seawater samples, 38 (19.8%) and 44 (22.9%) were positive for V. parahaemolyticus, producing green and mauve colonies on TCBS agar and CaV medium, respectively. Among 120 isolates of V. parahaemolyticus isolated in this study, 3 (2.5%) and 26 (21.7%) isolates of V. parahaemolyticus isolated without and with IMB treatment tested positive for the toxin regulatory (toxR) gene, respectively. Screening of the confirmed toxR gene-positive isolates revealed that 21 (17.5%) and 3 (2.5%) were positive for the thermostable direct hemolysin (tdh) encoding gene in strains isolated with IMB and without IMB treatment, respectively. None of the V. parahaemolyticus strains tested positive for the thermostable related hemolysin (trh) gene. In this study, we found that the CaV medium has no advantage over TCBS agar if IMB concentration treatment is used during secondary enrichment steps of environmental samples. The enterobacterial repetitive intergenic consensus (ERIC)-PCR DNA fingerprinting analysis revealed high genomic diversity, and 18 strains of V. parahaemolyticus were grouped and identified into four identical ERIC clonal group patterns.

Conclusions

The presented study reports the first detection of tdh producing V. parahaemolyticus in coastal water in the Eastern Province of Saudi Arabia.

Evaluating the potential for exposure to organisms of public health concern in naturally occurring bathing waters in Europe: A scoping review

Globally, water-based bathing pastimes are important for both mental and physical health. However, exposure to waterborne organisms could present a substantial public health issue. Bathing waters are shown to contribute to the transmission of illness and disease and represent a reservoir and pathway for the dissemination of antimicrobial resistant (AMR) organisms. Current bathing water quality regulations focus on enumeration of faecal indicator organisms and are not designed for detection of specific waterborne organisms of public health concern (WOPHC), such as antimicrobial resistant (AMR)/pathogenic bacteria, or viruses. This investigation presents the first scoping review of the occurrence of waterborne organisms of public health concern (WOPHC) in identified natural bathing waters across the European Union (EU), which aimed to critically evaluate the potential risk of human exposure and to assess the appropriateness of the current EU bathing water regulations for the protection of public health. Accordingly, this review sought to identify and synthesise all literature pertaining to a selection of bacterial (Campylobacter spp., Escherichia coli, Salmonella spp., Shigella spp., Vibrio spp., Pseudomonas spp., AMR bacteria), viral (Hepatitis spp., enteroviruses, rotavirus, adenovirus, norovirus), and protozoan (Giardia spp., and Cryptosporidium spp.) contaminants in EU bathing waters. Sixty investigations were identified as eligible for inclusion and data was extracted. Peer-reviewed investigations included were from 18 countries across the EU, totalling 87 investigations across a period of 35 years, with 30% published between 2011 and 2015. A variety of water bodies were identified, with 27 investigations exclusively assessing coastal waters. Waterborne organisms were classified into three categories; bacteria, viruses, and protozoa; amounting to 58%, 36% and 17% of the total investigations, respectively. The total number of samples across all investigations was 8,118, with detection of one or more organisms in 2,449 (30%) of these. Viruses were detected in 1281 (52%) of all samples where WOPHC were found, followed by bacteria (865(35%)) and protozoa (303(12%)). Where assessed (442 samples), AMR bacteria had a 47% detection rate, emphasising their widespread occurrence in bathing waters. Results of this scoping review highlight the potential public health risk of exposure to WOPHC in bathing waters that normally remain undetected within the current monitoring parameters.

Heatwave-associated Vibrio infections in Germany, 2018 and 2019

Background

Vibrio spp. are aquatic bacteria that prefer warm seawater with moderate salinity. In humans, they can cause gastroenteritis, wound infections, and ear infections. During the summers of 2018 and 2019, unprecedented high sea surface temperatures were recorded in the German Baltic Sea.

Aim

We aimed to describe the clinical course and microbiological characteristics of Vibrio infections in Germany in 2018 and 2019.

Methods

We performed an observational retrospective multi-centre cohort study of patients diagnosed with domestically-acquired Vibrio infections in Germany in 2018 and 2019. Demographic, clinical, and microbiological data were assessed, and isolates were subjected to whole genome sequencing and antimicrobial susceptibility testing.

Results

Of the 63 patients with Vibrio infections, most contracted the virus between June and September, primarily in the Baltic Sea: 44 (70%) were male and the median age was 65 years (range: 2–93 years). Thirty-eight patients presented with wound infections, 16 with ear infections, six with gastroenteritis, two with pneumonia (after seawater aspiration) and one with primary septicaemia. The majority of infections were attributed to V. cholerae (non–O1/non-O139) (n = 30; 48%) or V. vulnificus (n = 22; 38%). Phylogenetic analyses of 12 available isolates showed clusters of three identical strains of V. vulnificus, which caused wound infections, suggesting that some clonal lines can spread across the Baltic Sea.

Conclusions

During the summers of 2018 and 2019, severe heatwaves facilitated increased numbers of Vibrio infections in Germany. Since climate change is likely to favour the proliferation of these bacteria, a further increase in Vibrio-associated diseases is expected.

Environmental parameters associated with incidence and transmission of pathogenic Vibrio spp

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

[Non-cholera Vibrio species - currently still rare but growing danger of infection in the North Sea and the Baltic Sea]

BACKGROUND

The abundance of non-cholera Vibrio spp. in the aquatic environment shows a positive correlation with water temperatures. Therefore, climate change has an important impact on the epidemiology of human infections with these pathogens. In recent years large outbreaks have been repeatedly observed during the summer months in temperate climate zones.

OBJECTIVE

To inform medical professionals about the potentially life-threatening diseases caused by non-cholera Vibrio spp.

MATERIAL AND METHODS

Review of the current literature on infections with non-cholera Vibrio spp. in general and on the epidemiological situation in Germany in particular.

RESULTS

Non-cholera Vibrio spp. predominantly cause wound and ear infections after contact with contaminated seawater and gastroenteritis after consumption of undercooked seafood. As there have not been mandatory notification systems for these pathogens in Germany up to March 2020, a high number of unreported cases must be assumed. Immunosuppressed and chronically ill patients have a much higher risk for severe courses of diseases. If an infection with non-cholera Vibrio spp. is suspected anti-infective treatment should be promptly initiated and surgical cleansing is often necessary for wound and soft tissue infections.

CONCLUSION

Due to the ongoing global warming an increased incidence of human infections with non-cholera Vibrio spp. must be expected in the future. Medical professionals should be aware of these bacterial pathogens and the potentially life-threatening infections in order to enable timely diagnostics and treatment.

Effect of Seawater Temperature Increase on the Occurrence of Coastal Vibrio vulnificus Cases: Korean National Surveillance Data from 2003 to 2016

The purpose of this study was to assess the association between seawater temperature and Vibrio vulnificus cases in coastal regions of Korea. All V. vulnificus cases in coastal regions notified to the Korea Disease Control and Prevention Agency between 2003 and 2016 were included in this work. Data for seawater temperature on the south, west, and east coast during the study period were provided by the Korea Oceanographic Data Center of the National Institute of Fisheries Science. We used a generalized additive model and performed a negative binomial regression analysis. In total, 383 notified cases were analyzed (west coast: 196 cases, south coast: 162, and east coast: 25). The maximum seawater temperature was the most significant predictor of V. vulnificus cases on the south and east coasts (relative risk according to the 1 °C increase in seawater temperature (RR) = 1.35 (95% confidence interval (CI): 1.19–1.53) and 1.30 (95% CI: 1.06–1.59), respectively). However, the mean seawater temperature was the most significant predictor for the west coast (RR = 1.34 (95% CI: 1.20–1.51)). These results indicate that continuously monitoring seawater temperature increase in each coastal area is crucial to prevent V. vulnificus infections and protect high-risk groups, such as persons with liver disease.

Method for Specific Identification of the Emerging Zoonotic Pathogen Vibrio vulnificus Lineage 3 (Formerly Biotype 3)

Vibrio vulnificus is a zoonotic pathogen that is spreading worldwide due to global warming. Lineage 3 (L3; formerly biotype 3) includes the strains of the species with the unique ability to cause fish farm-linked outbreaks of septicemia. The L3 strains emerged recently and are particularly virulent and difficult to identify. Here, we describe a newly developed PCR method based on a comparative genomic study useful for both rapid identification and epidemiological studies of this interesting emerging group. The comparative genomic analysis also revealed the presence of a genetic duplication in the L3 strains that could be related to the unique ability of this lineage to produce septicemia outbreaks.

Chronic otitis media following infection by non-O1/non-O139 Vibrio cholerae: A case report and review of the literature

We report a case of a chronic mesotympanic otitis media with a smelly purulent secretion from both ears and recurrent otalgia over the last five years in a six-year-old girl after swimming in the German Baltic Sea. Besides Staphylococcus aureus a non-O1/non-O139 Vibrio cholerae strain could be isolated from patient samples. An antibiotic therapy with ciprofloxacin and ceftriaxone was administered followed by atticotomy combined with tympanoplasty. We conclude that V. cholerae should not be overlooked as a differential diagnosis to otitis infections, especially when patients present with extra-intestinal infections after contact with brackish- or saltwater aquatic environments.

Phenotypic and Genotypic Properties of Vibrio cholerae non-O1, non-O139 Isolates Recovered from Domestic Ducks in Germany

Vibrio cholerae non-O1, non-O139 bacteria are natural inhabitants of aquatic ecosystems and have been sporadically associated with human infections. They mostly lack the two major virulence factors of toxigenic V. cholerae serogroups O1 and O139 strains, which are the causative agent of cholera. Non-O1, non-O139 strains are found in water bodies, sediments, and in association with other aquatic organisms. Occurrence of these bacteria in fecal specimens of waterfowl were reported, and migratory birds likely contribute to the long-distance transfer of strains. We investigated four V. cholerae non-O1, non-O139 isolates for phenotypic traits and by whole genome sequencing (WGS). The isolates were recovered from organs of domestic ducks with serious disease symptoms. WGS data revealed only a distant genetic relationship between all isolates. The isolates harbored a number of virulence factors found in most V. cholerae strains. Specific virulence factors of non-O1, non-O139 strains, such as the type III secretion system (TTSS) or cholix toxin, were observed. An interesting observation is that all isolates possess multifunctional autoprocessing repeats-in-toxin toxins (MARTX) closely related to the MARTX of toxigenic El Tor O1 strains. Different primary sequences of the abundant OmpU proteins could indicate a significant role of this virulence factor. Phenotypic characteristics such as hemolysis and antimicrobial resistance (AMR) were studied. Three isolates showed susceptibility to a number of tested antimicrobials, and one strain possessed AMR genes located in an integron. Knowledge of the environmental occurrence of V. cholerae non-O1, non-O139 in Germany is limited. The source of the infection of the ducks is currently unknown. In the context of the ‘One Health’ concept, it is desirable to study the ecology of V. cholerae non-O1, non-O139, as it cannot be excluded that the isolates possess zoonotic potential and could cause infections in humans.

[Vibrio vulnificus, an increasing threat of sepsis in Germany?]

BACKGROUND

The prevalence of Vibrio vulnificus heavily depends on the temperature and salinity of the sea water. In the course of climate change an increase in cases of fatal sepsis caused by V. vulnificus at the German Baltic Sea coast could be detected.

OBJECTIVE

To generate awareness for a life-threatening infection with increasing incidence in Germany.

MATERIAL AND METHODS

This article presents an overview of the current state of the literature followed by an exemplary description of cases with V vulnificus sepsis caused by contact with water in the Baltic Sea, which were treated at the Medical University in Greifswald in summer 2018.

RESULTS

In the presence of risk factors, such as liver and kidney diseases, immunosuppression and male sex, there is a danger of severe sepsis if damaged skin comes into contact with contaminated sea water. A pronounced organ dysfunction can frequently be found on admission. In these cases the diagnosis must be made promptly and timely surgical cleansing and antibiotic treatment should be initiated (e.g. a combination of tetracyclines and third generation cephalosporins).

CONCLUSION

Sepsis due to V. vulnificus will probably increase over the coming years. Because there is a latency in some cases between infection and onset of sepsis, physicians beyond the coastal region must also be informed about this disease.

Environmental control of Vibrio spp. abundance and community structure in tropical waters

We measured Vibrio spp. distribution and community profile in the tropical estuary of Port Klang and coastal water of Port Dickson, Malaysia. Vibrio spp. abundance ranged from 15 to 2395 colony forming units mL-1, and was driven by salinity and chlorophyll a (Chl a) concentration. However, the effect of salinity was pronounced only when salinity was <20 ppt. A total of 27 Vibrio spp. were identified, and theVibrio spp. community at Port Dickson was more diverse (H' = 1.94 ± 0.21). However species composition between Port Dickson and Port Klang were similar. Two frequently occurring Vibrio spp. were V. owensii and V. rotiferianus, which exhibited relatively higher growth rates (ANCOVA: F > 4.338, P < 0.05). Co-culture experiments between fast- and slow-growing Vibrio spp. revealed that fast-growing Vibrio spp. (r-strategists) were overwhelmed by slower-growing Vibrio spp. (K-strategists) when nutrient conditions were set towards oligotrophy. In response to resource availability, the intrinsic growth strategy of each Vibrio spp. determined its occurrence and the development of Vibrio spp. community composition.

Phenotypic and Genotypic Characterization of Veterinary Vibrio cincinnatiensis Isolates

Vibrio cincinnatiensis is a halophilic species which has been found in marine and estuarine environments worldwide. The species is considered a rare pathogen for which the significance for humans is unclear. In this study, nine veterinary isolates were investigated that were obtained from domestic animals in Germany. The isolates were mostly recovered from abortion material of pigs, cattle, and horse (amnion or fetuses). One isolate was from a goose. A human clinical strain from a case of enteritis in Germany described in the literature was also included in the study. Whole-genome sequencing (WGS) of all isolates and MALDI-TOF MS (matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry) were performed to verify the species assignment. All strains were investigated for phenotypic traits including antimicrobial resistance (AMR), biochemical properties, and two virulence-associated phenotypes (hemolytic activity and resistance to human serum). WGS data and MS spectra confirmed that all veterinary isolates are closely related to the type strain V. cincinnatiensis NCTC12012. An exception was the human isolate from Germany which is related to the other isolates but could belong to another species. The isolates were similar in most biochemical phenotypes. Only one strain showed a very weak hemolytic activity against sheep erythrocytes, and serum resistance was intermediate in two strains. AMR phenotypes were more variable between the isolates. Resistances were observed against ß-lactams ampicillin and cefoxitin and against tetracycline and the sulfonamide antibiotics trimethoprim and sulfamethoxazole. Some acquired AMR genes were identified by bioinformatics analyses. WGS and MALDI-TOF MS data reveal a close relationship of the veterinary isolates and the type strain V. cincinnatiensis NCTC12012, which is a clinical human isolate. As the veterinary isolates of this study were mostly recovered from abortion material (amnions and fetuses), a zoonotic potential of the veterinary isolates seems possible.

Potentially human pathogenic Vibrio spp. in a coastal transect: Occurrence and multiple virulence factors

An increase in human Vibrio spp. infections has been linked to climate change related events, in particular to seawater warming and heatwaves. However, there is a distinct lack of research of pathogenic Vibrio spp. occurrences in the temperate North Sea, one of the fastest warming seas globally. Particularly in the German Bight, Vibrio investigations are still scarce. This study focuses on the spatio-temporal quantification and pathogenic characterization of V. parahaemolyticus, V. vulnificus and V. cholerae over the course of 14 months. Species-specific MPN-PCR (Most probable number - polymerase chain reaction) conducted on selectively enriched surface water samples revealed seasonal patterns of all three species with increased abundances during summer months. The extended period of warm seawater coincided with prolonged Vibrio spp. occurrences in the German Bight. Temperature and nitrite were the factors explaining variations in Vibrio spp. abundances after generalized additive mixed models. The specific detection of pathogenic markers via PCR revealed trh-positive V. parahaemolyticus, pathogenic V. vulnificus (nanA, manIIA, PRXII) and V. cholerae serotype O139 presence. Additionally, spatio-temporally varying virulence profiles of V. cholerae with multiple accessory virulence-associated genes, such as the El Tor variant hemolysin (hlyAET), acyltransferase of the repeats-in-toxin cluster (rtxC), Vibrio 7th pandemic island II (VSP-II), Type III Secretion System (TTSS) and the Cholix Toxin (chxA) were detected. Overall, this study highlights that environmental human pathogenic Vibrio spp. comprise a reservoir of virulence-associated genes in the German Bight, especially in estuarine regions. Due to their known vast genetic plasticity, we point to the possible emergence of highly pathogenic V. cholerae strains. Particularly, the presence of V. cholerae serotype O139 is unusual and needs urgent continuous surveillance. Given the predictions of further warming and more frequent heatwave events, human pathogenic Vibrio spp. should be seriously considered as a developing risk to human health in the German Bight.

First findings of potentially human pathogenic bacteria Vibrio in the south-eastern Baltic Sea coastal and transitional bathing waters

Vibrio spp. are bacteria that inhabit fresh and marine waters throughout the world and can cause severe infections in humans. This study aimed to investigate the presence of potentially pathogenic Vibrio bacteria in the coastal waters of the Lithuanian Baltic Sea and the Curonian Lagoon. The results of cultivation on TCBS media showed that total abundance of Vibrio spp. varied from 1.2 × 10² to 6 × 10⁴ CFU L^-1. Real-time PCR revealed that the V. vulnificus vvhA gene varied from 2.8 × 10³ to 3.7 × 10⁴ copies L^-1, with the highest amounts in sites with average water salinity of 7.1 PSU. Both green and blue-green algae and lower salinity play a role in the growth and spread of total Vibrio spp. Although potential infection risk was low at the time of this study, regular monitoring of Vibrio spp. and infection risk assessments are recommended.

Enteric viruses, somatic coliphages and Vibrio species in marine bathing and non-bathing waters in Italy

Microbial safety of recreational waters is a significant public health issue. In this study we assessed the occurrence and quantity of enteric viruses in bathing and non-bathing waters in Italy, in parallel with microbial faecal indicators, somatic coliphages and Vibrio spp. Enteric viruses (aichivirus, norovirus and enterovirus) were detected in 55% of bathing water samples, including samples with bacterial indicator concentrations compliant with the European bathing water Directive. Aichivirus was the most frequent and abundant virus. Adenovirus was detected only in non-bathing waters. Somatic coliphages were identified in 50% bathing water samples, 80% of which showed simultaneous presence of viruses. Vibrio species were ubiquitous, with 9 species identified, including potential pathogens (V. cholerae, V. parahaemoylticus and V. vulnificus). This is the first study showing the occurrence and high concentration of Aichivirus in bathing waters and provides original information, useful in view of a future revision of the European Directive.

Environmental Reservoirs of Vibrio cholerae: Challenges and Opportunities for Ocean-Color Remote Sensing

The World Health Organization has estimated the burden of the on-going pandemic of cholera at 1.3 to 4 million cases per year worldwide in 2016, and a doubling of case-fatality-rate to 1.8% in 2016 from 0.8% in 2015. The disease cholera is caused by the bacterium Vibrio cholerae that can be found in environmental reservoirs, living either in free planktonic form or in association with host organisms, non-living particulate matter or in the sediment, and participating in various biogeochemical cycles. An increasing number of epidemiological studies are using land- and water-based remote-sensing observations for monitoring, surveillance, or risk mapping of Vibrio pathogens and cholera outbreaks. Although the Vibrio pathogens cannot be sensed directly by satellite sensors, remotely-sensed data can be used to infer their presence. Here, we review the use of ocean-color remote-sensing data, in conjunction with information on the ecology of the pathogen, to map its distribution and forecast risk of disease occurrence. Finally, we assess how satellite-based information on cholera may help support the Sustainable Development Goals and targets on Health (Goal 3), Water Quality (Goal 6), Climate (Goal 13), and Life Below Water (Goal 14).

Application of gyrB targeted SYBR green based qPCR assay for the specific and rapid detection of Vibrio vulnificus in seafood

A SYBR green based qPCR assay targeting a unique region of gyrB was developed for the detection of Vibrio vulnificus. The specificity of the assay was studied using V. vulnificus and other bacterial strains belonging to Vibrio and non-Vibrio species. The assay unambiguously distinguished V.vulnificus with a sensitivity of 10¹ CFU/mL in pure culture while 10²CFU/g was detected in clam meat homogenate with an efficiency of ≥98%.The utility of the qPCR assay was validated with naturally incurred seafood samples, where 24 out of 59(40.67%) seafood samples tested positive for V. vulnificus after 6-8 h enrichment in APW-P broth. In contrast, conventional PCR could detect only 11 samples (18.64%). Our results showed that qPCR assay developed in this study could be used as a rapid method for screening seafood samples for the presence of V. vulnificus, as the assay can be completed within 9-12 h including the enrichment of seafood in APW-P broth. The gyrB targeted qPCR developed in this study can provide excellent results on the presence and load of V. vulnificus in naturally contaminated samples quickly and efficiently; thus it could find application as a routine test in the seafood industry for the analysis V. vulnificus.

The release of a distinct cell type from swarm colonies facilitates dissemination of Vibrio parahaemolyticus in the environment

Bacteria experience changes in their environment and have developed various strategies to respond accordingly. To accommodate environmental changes, certain bacteria differentiate between specialized cell types. Vibrio parahaemolyticus is a marine bacterium, a worldwide human pathogen and the leading agent of seafood-borne gastroenteritis. It exists as swimmer or swarmer cells, specialized for life in liquid and on solid environments, respectively. Swarmer cells are characteristically highly elongated-a morphology important for swarming behavior. When attached to surfaces it forms swarm colonies, however, it is not known how cells within swarming populations respond to changes in the external milieu and how its distinct life cycle influences its ecological dissemination. The worldwide distribution of V. parahaemolyticus accentuates the need for understanding the factors contributing to its dissemination. Here we determine the stage-wise development of swarm colonies and show how the swarm colony architecture fluctuates with changing environmental conditions. Swarm colonies act as a continuous source of cells that are released from the swarm colony into the environment. Surprisingly, the cell length distribution of released cells was very homogenous and almost no long cells were detected, indicating that swarmer cells are not released into the liquid environment but stay surface attached during flooding. Released cells comprise a distinct cell type that is morphologically optimized for swimming behavior and is capable of spreading in the liquid environment and attach to new surfaces. Release of this distinct cell type facilitates the dissemination of V. parahaemolyticus in the environment and likely influences the ecology of this bacterium.

Spatial Heterogeneity of Vibrio spp. in Sediments of Chinese Marginal Seas

Vibrio spp. are ubiquitous marine bacteria with high metabolism flexibility and genome plasticity. Previous studies have revealed the dynamics of planktonic vibrios in relation to environmental forces, such as temperature and salinity. However, little is known about Vibrio ecology in benthic environments. Here, we elucidate the abundance, diversity, and spatial distribution of Vibrio spp. in sediments of the Chinese marginal seas, with a wide spatial range from north to south covering the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Quantitative analysis showed that Vibrio spp. were most abundant in the SCS (∼9.04 × 10⁵ copies/g) compared to the YS (∼1.00 × 10⁵ copies/g) and ECS (∼8.86 × 10⁵ copies/g). Vibrio community compositions derived from Illumina sequencing of Vibrio-specific 16S rRNA genes varied significantly between sampling areas, which was reflected by a strong distance-decay pattern. The spatial distribution of Vibrio was governed by a joint effect of spatial and environmental factors (especially temperature, salinity, and SiO₃ ^2-), and their respective pure effects explained only a small fraction of the community variation. Moreover, we identified the most prominent operational taxonomic units (OTUs) that were partitioned in these sea areas. Whereas Vibrionaceae OTU20 and Photobacterium lipolyticum were prevalent in the YS, Vibrio gigantis and Photobacterium piscicola, and P. piscicola, Photobacterium lutimaris, and Photobacterium alginatilyticum were prevalent in the ECS and SCS, respectively. Our study demonstrated clear spatial heterogeneity of Vibrio spp. in sediments of the Chinese marginal seas, laying a foundation for fully understanding the marine Vibrio ecology and the ecological roles of the species.IMPORTANCE Vibrio is an important component of natural marine microbial populations in terms of pathogenicity and roles in carbon cycling. Compared to the marine pelagic environment, our knowledge of the diversity and distribution pattern of Vibrio spp. in sediment is limited. Here, we show higher Vibrio abundance in Chinese marginal seas than in other studied sediments. There was a clear spatial differentiation of Vibrio abundance and community composition in different sea areas. The benthic Vibrio community displayed a strong distance-decay pattern across a wide spatial range, which was formed under the combined effects of spatial and environmental factors. These results provide deep insights into the ecological dynamics of Vibrio and its environmental controls, facilitating a more comprehensive understanding of the marine Vibrio ecology.

Environmental and Clinical Strains of Vibrio cholerae Non-O1, Non-O139 From Germany Possess Similar Virulence Gene Profiles

Vibrio cholerae is a natural inhabitant of aquatic ecosystems globally. Strains of the serogroups O1 and O139 cause the epidemic diarrheal disease cholera. In Northern European waters, V. cholerae bacteria belonging to other serogroups (designated non-O1, non-O139) are present, of which some strains have been associated with gastrointestinal infections or extraintestinal infections, like wound infections or otitis. For this study, environmental strains from the German coastal waters of the North Sea and the Baltic Sea were selected (100 strains) and compared to clinical strains (10 isolates) that were from patients who contracted the infections in the same geographical region. The strains were characterized by MLST and examined by PCR for the presence of virulence genes encoding the cholera toxin, the toxin-coregulated pilus (TCP), and other virulence-associated accessory factors. The latter group comprised hemolysins, RTX toxins, cholix toxin, pandemic islands, and type III secretion system (TTSS). Phenotypic assays for hemolytic activity against human and sheep erythrocytes were also performed. The results of the MLST analysis revealed a considerable heterogeneity of sequence types (in total 74 STs). The presence of virulence genes was also variable and 30 profiles were obtained by PCR. One profile was found in 38 environmental strains and six clinical strains. Whole genome sequencing (WGS) was performed on 15 environmental and 7 clinical strains that were ST locus variants in one, two, or three alleles. Comparison of WGS results revealed that a set of virulence genes found in some clinical strains is also present in most environmental strains irrespective of the ST. In few strains, more virulence factors are acquired through horizontal gene transfer (i.e., TTSS, genomic islands). A distinction between clinical and environmental strains based on virulence gene profiles is not possible for our strains. Probably, many virulence traits of V. cholerae evolved in response to biotic and abiotic pressure and serve adaptation purposes in the natural aquatic environment, but provide a prerequisite for infection of susceptible human hosts. These findings indicate the need for surveillance of Vibrio spp. in Germany, as due to global warming abundance of Vibrio will rise and infections are predicted to increase.

Environmental and hydroclimatic factors influencing Vibrio populations in the estuarine zone of the Bengal delta

The objective of this study was to determine environmental parameters driving Vibrio populations in the estuarine zone of the Bengal delta. Spatio-temporal data were collected at river estuary, mangrove, beach, pond, and canal sites. Effects of salinity, tidal amplitude, and a cyclone and tsunami were included in the study. Vibrio population shifts were found to be correlated with tide-driven salinity and suspended particulate matter (SPM). Increased abundance of Vibrio spp. in surface water was observed after a cyclone, attributed to re-suspension of benthic particulate organic carbon (POC), and increased availability of chitin and dissolved organic carbon (DOC). Approximately a two log₁₀ increase in the (p < 0.05) number of Vibrio spp. was observed in < 20 μm particulates, compared with microphytoplankton (20-60 μm) and zooplankton > 60 μm fractions. Benthic and suspended sediment comprised a major reservoir of Vibrio spp. Results of microcosm experiments showed enhanced growth of vibrios was related to concentration of organic matter in SPM. It is concluded that SPM, POC, chitin, and salinity significantly influence abundance and distribution of vibrios in the Bengal delta estuarine zone.

Ports and pests: Assessing the threat of aquatic invasive species introduced by maritime shipping activity in Cuba

Aquatic invasive species (AIS) are biological pollutants that cause detrimental ecological, economic, and human-health effects in their introduced communities. With increasing globalization through maritime trade, ports are vulnerable to AIS exposure via commercial vessels. The Cuban Port of Mariel is poised to become a competitive transshipment hub in the Caribbean and the intent of this study was to evaluate present and potential impacts AIS pose with the likely future increase in shipping activity. We utilized previous assessment frameworks and publicly accessible information to rank AIS by level of threat. Fifteen AIS were identified in Cuba and one, the Asian green mussel Perna viridis (Linnaeus, 1758), had repeated harmful economic impacts. Five species associated with trade partners of Port Mariel were considered potentially detrimental to Cuba if introduced through shipping routes. The results presented herein identify species of concern and emphasize the importance of prioritizing AIS prevention and management within Cuba.

Environmental Determinants of Vibrio parahaemolyticus in the Chesapeake Bay

Vibrio parahaemolyticus naturally occurs in brackish and marine waters and is one of the leading causes of seafood-borne illness. Previous work studying the ecology of V. parahaemolyticus has often been limited in geographic extent and lacked a full range of environmental measures. This study used a unique large data set of surface water samples in the Chesapeake Bay (n = 1,385) collected from 148 monitoring stations from 2007 to 2010. Water was analyzed for more than 20 environmental parameters, with additional meteorological and surrounding land use data. The V. parahaemolyticus-specific genetic markers thermolabile hemolysin (tlh), thermostable direct hemolysin (tdh), and tdh-related hemolysin (trh) were assayed using quantitative PCR (qPCR), and interval-censored regression models with nonlinear effects were estimated to account for limits of detection and quantitation. tlh was detected in 19.6% of water samples; tdh or trh markers were not detected. The results confirmed previously reported positive associations for V. parahaemolyticus abundance with temperature and turbidity and negative associations with high salinity (>10 to 23‰). Furthermore, the salinity relationship was determined to be a function of both low temperature and turbidity, with an increase of either nullifying the high salinity effect. Associations with dissolved oxygen and phosphate also appeared stronger when samples were taken near human developments. A renewed focus on the V. parahaemolyticus ecological paradigm is warranted to protect public health.IMPORTANCE Vibrio parahaemolyticus is one of the leading causes of seafood-borne illness in the United States and across the globe. Exposure is often through consuming raw or undercooked shellfish. Given the natural presence of the bacterium in the marine environment, an improved understanding of its environmental determinants is necessary for future preventative measures. This analysis of environmental Vibrio parahaemolyticus is one of only a few that utilize a large data set measured over a wide geographic and temporal range. The analysis also includes a large number of environmental parameters for Vibrio modeling, many of which have previously only been tested sporadically, and some of which have not been considered before. The results of the analysis revealed previously unknown relationships between salinity, turbidity, and temperature that provide significant insight into the abundance and persistence of V. parahaemolyticus bacterium in the environment. This information will be essential for developing environmental forecast models for the bacterium.

Environmental Suitability of Vibrio Infections in a Warming Climate: An Early Warning System

BACKGROUND

Some Vibrio spp. are pathogenic and ubiquitous in marine waters with low to moderate salinity and thrive with elevated sea surface temperature (SST).

OBJECTIVES

Our objective was to monitor and project the suitability of marine conditions for Vibrio infections under climate change scenarios.

METHODS

The European Centre for Disease Prevention and Control (ECDC) developed a platform (the ECDC Vibrio Map Viewer) to monitor the environmental suitability of coastal waters for Vibrio spp. using remotely sensed SST and salinity. A case-crossover study of Swedish cases was conducted to ascertain the relationship between SST and Vibrio infection through a conditional logistic regression. Climate change projections for Vibrio infections were developed for Representative Concentration Pathway (RCP) 4.5 and RCP 8.5.

RESULTS

The ECDC Vibrio Map Viewer detected environmentally suitable areas for Vibrio spp. in the Baltic Sea in July 2014 that were accompanied by a spike in cases and one death in Sweden. The estimated exposure-response relationship for Vibrio infections at a threshold of 16°C revealed a relative risk (RR)=1.14 (95% CI: 1.02, 1.27; p=0.024) for a lag of 2 wk; the estimated risk increased successively beyond this SST threshold. Climate change projections for SST under the RCP 4.5 and RCP 8.5 scenarios indicate a marked upward trend during the summer months and an increase in the relative risk of these infections in the coming decades.

CONCLUSIONS

This platform can serve as an early warning system as the risk of further Vibrio infections increases in the 21st century due to climate change. https://doi.org/10.1289/EHP2198.

Vibrio vulnificus VvhA induces Th1 and Tfh cells to proliferate against Vibrio vulnificus in a mouse model of infection

AIM

To characterize the roles of VvhA in host's acquired immune response to Vibrio vulnificus infection.

MATERIALS & METHODS

The recombinant VvhA fusion protein was used to immunize mice and the anti-VvhA polyclonal antibody was produced in vivo for prophylactic and therapeutic efficacy assay. The roles of VvhA in T helper (Th) cells differentiation were analyzed by vvhA-deleted mutant during the early phase of infection, while the ratio of Th2 and T follicular helper (Tfh) cells were examined in VvhA immunization.

RESULTS

Anti-VvhA antibody exhibited neutralization activity against V. vulnificus. Wild-type strain induced higher level of Th1 cells than the mutant, and the concentrations of IgG2a and IFN-γ were increased during the early phase of infection. The spontaneous development of Tfh was observed in immunized model, and the serum IL-21 was increased.

CONCLUSION

V. vulnificus VvhA elicited cellular and humoral immune responses by Th1 and Tfh cells to provide protection against VvhA.

Season-Specific Occurrence of Potentially Pathogenic Vibrio spp. on the Southern Coast of South Korea

Vibrio species are widely distributed in warm estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated seafood. In this study, we aimed to isolate and observe the distribution of enteropathogenic Vibrio spp. from environments of the southern coast of South Korea over a season cycle. A total of 10,983 isolates of Vibrio spp. were obtained from tidal water and mud samples over a 1-year period from five sampling sites along the southwest coast of South Korea. We found that Vibrio alginolyticus (n = 6,262) and Vibrio parahaemolyticus (n = 1,757) were ubiquitous in both tidal water and mud year round, whereas Vibrio cholerae (n = 24) and Vibrio vulnificus (n = 130) were seasonally specific to summer. While all V. cholerae isolates were nontoxigenic (non-O1 and non-O139), more than 88% of V. vulnificus isolates possessed the virulence factor elastolytic protease (encoded by vvp). Interestingly, V. parahaemolyticus, which was omnipresent in all seasons, contained the virulence factors thermostable direct hemolysin (encoded by tdh) and thermostable direct hemolysin-related hemolysin (encoded by trh) in larger amounts in June (29 trh-positive strains) and September (14 tdh-, 36 trh-, and 12 tdh- and trh-positive strains) than in December (4 trh-positive strains) and February (3 tdh-positive strains), and virulence factors were absent from isolates detected in April. To understand why virulence factors were detected only in the warm season and were absent in the cold season although the locations are static, long-term monitoring and particularly seasonal study are necessary.

IMPORTANCE

The presence of enteropathogenic Vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus), which cause acute diarrheal infection, septicemia, and wound infections upon ingestion through food and water, is usually associated with temperature. The World Health Organization (WHO) has estimated that there are 1.4 to 4.3 million cases and 28,000 to 142,000 deaths per year worldwide caused by cholera disease. In South Korea alone, consumption is as much as 52.4 kg of fish and shellfish per year per capita. Our findings suggested that seasonally specific acceleration of these possible pathogenic Vibrio spp. may threaten seafood safety and increase the risk of illness in South Korea, where local people consume raw fish during warmer months.

Cross-protection against Vibrio cholerae infection by monoclonal antibodies against Vibrio vulnificus RtxA1/MARTXVv

Gram-negative Vibrio species secrete multifunctional autoprocessing repeats-in-toxin (MARTX) toxins associated with bacterial pathogenesis. Here, the cross-reactivity and cross-protectivity of mAbs against V. vulnificus RtxA1/MARTX_Vv was evaluated. Passive administration of any of these mAbs (21RA, 24RA, 46RA, 47RA and 50RA) provided strong protection against lethal V. cholerae infection. Interestingly, 24RA and 46RA, which map to the cysteine protease domain of V. cholerae MARTX_Vc , inhibited CPD autocleavage in vitro; this process is involved in V. cholerae pathogenesis. These results generate new insight into the development of broadly protective mAbs and/or vaccines against Vibrio species with MARTX toxins.

Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles

The taxonomic composition of biofilms on marine microplastics is widely unknown. Recent sequencing results indicate that potentially pathogenic Vibrio spp. might be present on floating microplastics. Hence, these particles might function as vectors for the dispersal of pathogens. Microplastics and water samples collected in the North and Baltic Sea were subjected to selective enrichment for pathogenic Vibrio species. Bacterial colonies were isolated from CHROMagar™Vibrio and assigned to Vibrio spp. on the species level by MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionisation - Time of Flight Mass Spectrometry). Respective polymers were identified by ATR FT-IR (Attenuated Total Reflectance Fourier Transform - Infrared Spectroscopy). We discovered potentially pathogenic Vibrio parahaemolyticus on a number of microplastic particles, e.g. polyethylene, polypropylene and polystyrene from North/Baltic Sea. This study confirms the indicated occurrence of potentially pathogenic bacteria on marine microplastics and highlights the urgent need for detailed biogeographical analyses of marine microplastics.

Genotyping bacterial and fungal pathogens using sequence variation in the gene for the CCA-adding enzyme

BACKGROUND

To allow an immediate treatment of an infection with suitable antibiotics and bactericides or fungicides, there is an urgent need for fast and precise identification of the causative human pathogens. Methods based on DNA sequence comparison like 16S rRNA analysis have become standard tools for pathogen verification. However, the distinction of closely related organisms remains a challenging task. To overcome such limitations, we identified a new genomic target sequence located in the single copy gene for tRNA nucleotidyltransferase fulfilling the requirements for a ubiquitous, yet highly specific DNA marker. In the present study, we demonstrate that this sequence marker has a higher discriminating potential than commonly used genotyping markers in pro- as well as eukaryotes, underscoring its applicability as an excellent diagnostic tool in infectology.

RESULTS

Based on phylogenetic analyses, a region within the gene for tRNA nucleotidyltransferase (CCA-adding enzyme) was identified as highly heterogeneous. As prominent examples for pro- and eukaryotic pathogens, several Vibrio and Aspergillus species were used for genotyping and identification in a multiplex PCR approach followed by gel electrophoresis and fluorescence-based product detection. Compared to rRNA analysis, the selected gene region of the tRNA nucleotidyltransferase revealed a seven to 30-fold higher distinction potential between closely related Vibrio or Aspergillus species, respectively. The obtained data exhibit a superb genome specificity in the diagnostic analysis. Even in the presence of a 1,000-fold excess of human genomic DNA, no unspecific amplicons were produced.

CONCLUSIONS

These results indicate that a relatively short segment of the coding region for tRNA nucleotidyltransferase has a higher discriminatory potential than most established diagnostic DNA markers. Besides identifying microbial pathogens in infections, further possible applications of this new marker are food hygiene controls or metagenome analyses.

Virulence Profiles of Vibrio vulnificus in German Coastal Waters, a Comparison of North Sea and Baltic Sea Isolates

Vibrio vulnificus is a halophilic bacterium of coastal environments known for sporadically causing severe foodborne or wound infections. Global warming is expected to lead to a rising occurrence of V. vulnificus and an increasing incidence of human infections in Northern Europe. So far, infections in Germany were exclusively documented for the Baltic Sea coast, while no cases from the North Sea region have been reported. Regional variations in the prevalence of infections may be influenced by differences in the pathogenicity of V. vulnificus populations in both areas. This study aimed to compare the distribution of virulence-associated traits and genotypes among 101 V. vulnificus isolates from the Baltic Sea and North Sea in order to assess their pathogenicity potential. Furthermore, genetic relationships were examined by multilocus sequence typing (MLST). A high diversity of MLST sequences (74 sequence types) and differences regarding the presence of six potential pathogenicity markers were observed in the V. vulnificus populations of both areas. Strains with genotypes and markers associated with pathogenicity are not restricted to a particular geographic region. This indicates that lack of reported cases in the North Sea region is not caused by the absence of potentially pathogenic strains.

Environmental influences on the seasonal distribution of Vibrio parahaemolyticus in the Pacific Northwest of the USA

Populations of Vibrio parahaemolyticus in the environment can be influenced by numerous factors. We assessed the correlation of total (tl+) and potentially virulent (tdh+) V. parahaemolyticus in water with three harmful algal bloom (HAB) genera (Pseudo-nitzschia, Alexandrium and Dinophysis), the abundance of diatoms and dinoflagellates, chlorophyll-a and temperature, salinity and macronutrients at five sites in Washington State from 2008-2009. The variability in V. parahaemolyticus density was explained predominantly by strong seasonal trends where maximum densities occurred in June, 2 months prior to the highest seasonal water temperature. In spite of large geographic differences in temperature, salinity and nutrients, there was little evidence of corresponding differences in V. parahaemolyticus density. In addition, there was no evident relationship between V. parahaemolyticus and indices of HAB genera, perhaps due to a lack of significant HAB events during the sampling period. The only nutrient significantly associated with V. parahaemolyticus density after accounting for the seasonal trend was silicate. This negative relationship may be caused by a shift in cell wall structure for some diatom species to a chitinous substrate preferred by V. parahaemolyticus. Results from our study differ from those in other regions corroborating previous findings that environmental factors that trigger vibrio and HAB events may differ depending on geographic locations. Therefore caution should be used when applying results from one region to another.

A global map of suitability for coastal Vibrio cholerae under current and future climate conditions

Vibrio cholerae is a globally distributed water-borne pathogen that causes severe diarrheal disease and mortality, with current outbreaks as part of the seventh pandemic. Further understanding of the role of environmental factors in potential pathogen distribution and corresponding V. cholerae disease transmission over time and space is urgently needed to target surveillance of cholera and other climate and water-sensitive diseases. We used an ecological niche model (ENM) to identify environmental variables associated with V. cholerae presence in marine environments, to project a global model of V. cholerae distribution in ocean waters under current and future climate scenarios. We generated an ENM using published reports of V. cholerae in seawater and freely available remotely sensed imagery. Models indicated that factors associated with V. cholerae presence included chlorophyll-a, pH, and sea surface temperature (SST), with chlorophyll-a demonstrating the greatest explanatory power from variables selected for model calibration. We identified specific geographic areas for potential V. cholerae distribution. Coastal Bangladesh, where cholera is endemic, was found to be environmentally similar to coastal areas in Latin America. In a conservative climate change scenario, we observed a predicted increase in areas with environmental conditions suitable for V. cholerae. Findings highlight the potential for vulnerability maps to inform cholera surveillance, early warning systems, and disease prevention and control.

Development and characterization of a catalytically inactive cysteine protease domain of RtxA1/MARTXVv as a potential vaccine for Vibrio vulnificus

Recent studies have defined several virulence factors as vaccine candidates against Vibrio vulnificus. However, most of these factors have the potential to cause pathogenic effects in the vaccinees or induce incomplete protection. To overcome these drawbacks, a catalytically inactive form, CPDVv (C3725S), of the well-conserved cysteine protease domain (CPD) of V. vulnificus multifunctional autoprocessing repeats-in-toxin (MARTXVv /RtxA1) was recombinantly generated and characterized. Notably, active and passive immunization with CPDVv (C3725S) conferred protective immunity against V. vulnificus strains. These results may provide a novel framework for developing safe and efficient subunit vaccines and/or therapeutics against V. vulnificus that target the CPD of MARTX toxins.

Evaluation of recombinant leukocidin domain of VvhA exotoxin of Vibrio vulnificus as an effective toxoid in mouse model

Vibrio vulnificus hemolysin A (VvhA) is a pore forming toxin and plays an important role in the pathogenesis. The hemolytic and cytotytic property of VvhA toxin is associated with N-terminal leukocidin domain which triggers apoptotic signaling cascade in epithelial cells. The present study was undertaken to assess the protective efficacy of recombinant VvhA leukocidin domain (rL/VvhA) against VvhA toxin challenge using in vitro and in vivo assays. The rL/VvhA protein was found to be non-toxic with no significant hemolytic or cytotoxic effects. Intraperitoneal (I.P.) immunization of BALB/c mice with rL/VvhA protein elicited significantly higher specific serum antibody titer with mixed Th1/Th2 mediated immune responses. HeLa cell monolayer supplemented with anti-rL/VvhA antibodies were effectively protected (viability 86.69%) against lethal 5 LD50 toxin challenge. An effective in vitro proliferation of lymphocyte was observed upon re-stimulation of rL/VvhA primed splenocytes with formalin inactivated VvhA toxin (fVvhA). Co-expression of Th1/Th2 polarized cytokines (IFN-γ, IL-12 and IL-4), were seen in the cell culture supernatant. In contrast to sham immunized mice, rL/VvhA immunized mice demonstrated significant protection (90% survival) against native toxin challenge in vitro and in vivo infection models. These results suggested leukocidin domain of the VvhA toxin as protective immunogen for possible protection against V. vulnificus VvhA.

Influence of Environmental Factors on Vibrio spp. in Coastal Ecosystems

Various studies have examined the relationships between vibrios and the environmental conditions surrounding them. However, very few reviews have compiled these studies into cohesive points. This may be due to the fact that these studies examine different environmental parameters, use different sampling, detection, and enumeration methodologies, and occur in diverse geographic locations. The current article is one approach to compile these studies into a cohesive work that assesses the importance of environmental determinants on the abundance of vibrios in coastal ecosystems.

The Fish Pathogen Vibrio vulnificus Biotype 2: Epidemiology, Phylogeny, and Virulence Factors Involved in Warm-Water Vibriosis

Vibrio vulnificus biotype 2 is the etiological agent of warm-water vibriosis, a disease that affects eels and other teleosts, especially in fish farms. Biotype 2 is polyphyletic and probably emerged from aquatic bacteria by acquisition of a transferable virulence plasmid that encodes resistance to innate immunity of eels and other teleosts. Interestingly, biotype 2 comprises a zoonotic clonal complex designated as serovar E that has extended worldwide. One of the most interesting virulence factors produced by serovar E is RtxA1 3 , a multifunctional protein that acts as a lethal factor for fish, an invasion factor for mice, and a survival factor outside the host. Two practically identical copies of rtxA1 3 are present in all biotype 2 strains regardless of the serovar, one in the virulence plasmid and the other in chromosome II. The plasmid also contains other genes involved in survival and growth in eel blood: vep07 , a gene for an outer membrane (OM) lipoprotein involved in resistance to eel serum and vep20 , a gene for an OM receptor specific for eel-transferrin and, probably, other related fish transferrins. All the three genes are highly conserved within biotype 2, which suggests that they are under a strong selective pressure. Interestingly, the three genes are related with transferable plasmids, which emphasizes the role of horizontal gene transfer in the evolution of V. vulnificus in nutrient-enriched aquatic environments, such as fish farms.

Characterization of trh2 harbouring Vibrio parahaemolyticus strains isolated in Germany

BACKGROUND

Vibrio parahaemolyticus is a recognized human enteropathogen. Thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) as well as the type III secretion system 2 (T3SS2) are considered as major virulence factors. As tdh positive strains are not detected in coastal waters of Germany, we focused on the characterization of trh positive strains, which were isolated from mussels, seawater and patients in Germany.

RESULTS

Ten trh harbouring V. parahaemolyticus strains from Germany were compared to twenty-one trh positive strains from other countries. The complete trh sequences revealed clustering into three different types: trh1 and trh2 genes and a pseudogene Ψtrh. All German isolates possessed alleles of the trh2 gene. MLST analysis indicated a close relationship to Norwegian isolates suggesting that these strains belong to the autochthonous microflora of Northern Europe seawaters. Strains carrying the pseudogene Ψtrh were negative for T3SS2β effector vopC. Transcription of trh and vopC genes was analyzed under different growth conditions. Trh2 gene expression was not altered by bile while trh1 genes were inducible. VopC could be induced by urea in trh2 bearing strains. Most trh1 carrying strains were hemolytic against sheep erythrocytes while all trh2 positive strains did not show any hemolytic activity. TRH variants were synthesized in a prokaryotic cell-free system and their hemolytic activity was analyzed. TRH1 was active against sheep erythrocytes while TRH2 variants were not active at all.

CONCLUSION

Our study reveals a high diversity among trh positive V. parahaemolyticus strains. The function of TRH2 hemolysins and the role of the pseudogene Ψtrh as pathogenicity factors are questionable. To assess the pathogenic potential of V. parahaemolyticus strains a differentiation of trh variants and the detection of T3SS2β components like vopC would improve the V. parahaemolyticus diagnostics and could lead to a refinement of the risk assessment in food analyses and clinical diagnostics.

Effects of climate change on the persistence and dispersal of foodborne bacterial pathogens in the outdoor environment: A review

According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts.

VibrioBase: A MALDI-TOF MS database for fast identification of Vibrio spp. that are potentially pathogenic in humans

Mesophilic marine bacteria of the family Vibrionaceae, specifically V. cholerae, V. parahaemolyticus and V. vulnificus, are considered to cause severe illness in humans. Due to climate-change-driven temperature increases, higher Vibrio abundances and infections are predicted for Northern Europe, which in turn necessitates environmental surveillance programs to evaluate this risk. We propose that whole-cell matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling is a promising tool for the fast and reliable species classification of environmental isolates. Because the reference database does not contain sufficient Vibrio spectra we generated the VibrioBase database in this study. Mass spectrometric data were generated from 997 largely environmental strains and filed in this new database. MALDI-TOF MS clusters were assigned based on the species classification obtained by analysis of partial rpoB (RNA polymerase beta-subunit) sequences. The affiliation of strains to species-specific clusters was consistent in 97% of all cases using both approaches, and the extended VibrioBase generated more specific species identifications with higher matching scores compared to the commercially available database. Therefore, we have made the VibrioBase database freely accessible, which paves the way for detailed risk assessment studies of potentially pathogenic Vibrio spp. from marine environments.