Epidemiological and environmental investigation of the 'big four' Vibrio species, 1994 to 2021: a Baltic Sea retrospective study.

BackgroundThe Vibrio genus comprises several bacterial species present in the Baltic Sea region (BSR), which are known to cause human infections.AimTo provide a comprehensive retrospective analysis of Vibrio-induced infections in the BSR from 1994 to 2021, focusing on the 'big four' Vibrio species - V. alginolyticus, V. cholerae non-O1/O139, V. parahaemolyticus and V. vulnificus - in eight European countries (Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland and Sweden) bordering the Baltic Sea.MethodsOur analysis includes data on infections, Vibrio species distribution in coastal waters and environmental data received from national health agencies or extracted from scientific literature and online databases. A redundancy analysis was performed to determine the potential impact of several independent variables, such as sea surface temperature, salinity, the number of designated coastal beaches and year, on the Vibrio infection rate.ResultsFor BSR countries conducting surveillance, we observed an exponential increase in total Vibrio infections (n = 1,553) across the region over time. In Sweden and Germany, total numbers of Vibrio spp. and infections caused by V. alginolyticus and V. parahaemolyticus positively correlate with increasing sea surface temperature. Salinity emerged as a critical driver of Vibrio spp. distribution and abundance. Furthermore, our proposed statistical model reveals 12 to 20 unreported cases in Lithuania and Poland, respectively, countries with no surveillance.ConclusionsThere are discrepancies in Vibrio surveillance and monitoring among countries, emphasising the need for comprehensive monitoring programmes of these pathogens to protect human health, particularly in the context of climate change.

Diverse sources of fecal contamination in macroalgae wrack-affected environment adjacent to river outflow along the Baltic Sea coast.

We investigated the dynamics of feces-associated microorganisms in areas with wrack accumulation in the southeastern part of the Baltic Sea. Our study covered single-day (2021 ) and multi-day (2022) observations during the recreational season. We collected water, sand, and wrack samples and assessed the abundance of fecal indicator bacteria (FIB), as well metagenomic analysis was conducted to monitor changes in microbial composition. Based on metagenomic data we identified taxa associated with feces, sewage, and ruminant sources. Human-related fecal pollution based on genetic markers correlated with the presence of Lachnospiraceae, Prevotellaceae and Rickenellacea abundance. Higher abundance and diversity of feces-associated and ruminant-associated taxa and the presence of enteric pathogens were observed when wrack accumulated near the river outflow in 2021, suggesting a potential link with fecal pollution from the river. As a preventive measure, it is recommended to remove the wrack to reduce the risk of exposure to potential enteric pathogens if it is accumulated next to the river outflow.

Microbial Composition Dynamics in Peloids Used for Spa Procedures in Lithuania: Pilot Study.

Despite peloids' acknowledged therapeutic and cosmetic potential, there remains a limited understanding of their microbial diversity and dynamics, especially concerning beneficial and non-beneficial microorganisms under different heating conditions. Our study employs both cultivation and metagenomic methods to assess the microbiota of peloids, focusing on lake sapropel and peat under heating conditions recommended for external application and safety assurance. By applying microbial indicators specified in national regulatory documents, we found that all peloids reached thresholds for sulphite-reducing clostridia and colony-forming units. Each peloid exhibited a distinctive bacterial composition based on metagenomic analysis, and temperature-induced changes were observed in microbial diversity. We identified beneficial bacteria potentially contributing to the therapeutic properties of peloids. However, the same peloids indicated the presence of bacteria of human faecal origin, with a notably higher abundance of Escherichia coli, pointing to a potential source of contamination. Unfortunately, it remains unclear at which stage this contamination entered the peloids. The findings underscore the importance of monitoring and controlling microbial aspects in peloid applications, emphasising the need for measures to prevent and address contamination during their preparation and application processes.

Impact of beach wrack on microorganisms associated with faecal pollution at the Baltic Sea Sandy beaches.

We investigated whether higher quantities of faecal indicator bacteria (FIB) are in the areas with red algae-dominated wrack compared to areas without it and if the birds are the primary source of faecal pollution on sandy beaches of the Baltic Sea. Water, sand and wrack samples were collected during the recreational season, and abundances of FIB, HF183 (human faecal pollution) and GFD (bird faecal pollution) markers, as well as the presence of Salmonella and Campylobacter, were assessed. Significantly higher levels of Enterococcus spp. were found in the wrack accumulation areas in water and sand than in the areas without wrack when there was a faecal pollution event, which could be explained by entrapment and changed physico-chemical water conditions. Both faecal pollution markers were identified, however, with no apparent pattern. Campylobacter bacteria were identified in the wrack-affected water, sand, and beach wrack. While this research provides valuable insights into beach wrack serving as a reservoir for FIB, further investigations, including multi-day samplings, are necessary to gain a deeper understanding of the long-term dynamics of microbiota within red algae-dominated wrack.

Biodiversity of microorganisms in the Baltic Sea: the power of novel methods in the identification of marine microbes.

Until recently, the data on the diversity of the entire microbial community from the Baltic Sea were relatively rare and very scarce. However, modern molecular methods have provided new insights into this field with interesting results. They can be summarized as follows. (i) Although low salinity causes a reduction in the biodiversity of multicellular species relative to the populations of the North-East Atlantic, no such reduction occurs in bacterial diversity. (ii) Among cyanobacteria, the picocyanobacterial group dominates when considering gene abundance, while filamentous cyanobacteria dominate in means of biomass. (iii) The diversity of diatoms and dinoflagellates is significantly larger than described a few decades ago; however, molecular studies on these groups are still scarce. (iv) Knowledge gaps in other protistan communities are evident. (v) Salinity is the main limiting parameter of pelagic fungal community composition, while the benthic fungal diversity is shaped by water depth, salinity, and sediment C and N availability. (vi) Bacteriophages are the predominant group of viruses, while among viruses infecting eukaryotic hosts, Phycodnaviridae are the most abundant; the Baltic Sea virome is contaminated with viruses originating from urban and/or industrial habitats. These features make the Baltic Sea microbiome specific and unique among other marine environments.

Macrophytes and their wrack as a habitat for faecal indicator bacteria and Vibrio in coastal marine environments.

Waterborne pathogenic bacteria, including faecal indicator bacteria and potentially pathogenic Vibrio, are a global concern for diseases transmitted through water. A systematic review was conducted to analyse publications that investigated these bacteria in relation to macrophytes (seagrasses and macroalgae) in coastal marine environments. The highest quantities of FIB were found on brown algae and seagrasses, and the highest quantities of Vibrio bacteria were on red algae. The most extensively studied macrophyte group was brown algae, green algae were the least researched. Macrophyte wrack was found to favor the presence of FIB, but there is a lack of information about Vibrio quantities in this environment. To understand the role of Vibrio bacteria that are pathogenic to humans, molecular methods complementary to cultivation methods should be used. Further research is needed to understand the underlying mechanisms of FIB and potentially pathogenic Vibrio with macrophytes and their microbiome in the coastal marine environment.

Characterization and Diversity of Microcystins Produced by Cyanobacteria from the Curonian Lagoon (SE Baltic Sea).

Microcystins (MCs) are the most widely distributed and structurally diverse cyanotoxins that can have significant health impacts on living organisms, including humans. The identification of MC variants and their quantification is very important for toxicological assessment. Within this study, we explored the diversity of MCs and their potential producers from the Curonian Lagoon. MC profiles were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, while the potential producers were detected based on the presence of genus-specific mcyE gene sequences. Among the numerous MCs detected, one new potential MC variant with m/z 1057 was partially characterized. Moreover, two other MCs with m/z 1075 and m/z 1068 might belong to new variants with serine (Ser), rarely detected in position one of the peptides. They might also represent MC-Y(OMe)R and MC-WR, respectively. However, the application of a low-resolution MS/MS system made the unambiguous identification of the MCs impossible. Based on this example, the problems of peptide structure identification are discussed in the work. Genetic analysis revealed that potential MCs producers include Dolichospermum/Anabaena, Microcystis spp., and Planktothrix agardhii. The diversity and temporal variations in MC profiles may indicate the presence of several chemotypes of cyanobacteria in the Curonian Lagoon.

Cigarette butts on Baltic Sea beaches: Monitoring, pollution and mitigation measures.

OSPAR, Rake and Flood accumulation zone methods were applied at 29 beaches of the German and Lithuanian Baltic Sea coast (2011-2018) to monitor cigarette butt pollution. Also, butt pollution prevention measure - ballot bin, was tested. The number of cigarette butts was significantly higher in Germany than in Lithuania, but the percent of butts from total litter items was similar. Rake method turned out to be suitable for cigarette butt assessment, while the OSPAR method underestimates the butt pollution. The visitor number on the beach had a significant effect on the cigarette butt number: in remote beaches, without visitors, usually, no butts were observed, while the highest number and the percent of butts were observed in beaches with the highest number of visitors. The ballot bin campaign may have increased the public awareness about pollution, but turned out to be in-efficient in reducing it.

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.

Long term development of Bathing Water Quality at the German Baltic coast: spatial patterns, problems and model simulations.

Bathing water quality plays a key role for public health, is highly important for recreational tourism and therefore monitored in the EU-Directive 2006/7/EC. To identify pollution hot spots, sources and impacts of the directive-change in 2006, including a change of indicator organisms, we evaluated monitoring data of the past 15 years, collected own data, determined survival rates of indicator organisms and applied hydrodynamic modelling in a micro-tidal-system. Due to higher survival rates under turbid conditions and restricted water exchange, shallow, eutrophic bays and lagoons are hot spots of microbial pollution. Rain events cause high microbial emission and distribution. Based on different decay rates, the ratio of E. coli to Enterococci can hint towards a pollution source. Including rain predictions, currents and winds, hydrodynamic models can then assess the daily risk of microbial pollution at each bathing site. They are an important tool to modify beach management and event-based monitoring.