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As plastic debris in the environment continues to increase, an emerging concern is the potential for microplastic to act as vectors for pathogen transport. With aquaculture the fastest growing food sector, and microplastic contamination of shellfish increasingly demonstrated, understanding any risk of pathogen transport associated with microplastic is important for this industry. However, there remains a lack of detailed, systematic studies assessing the interactions and potential impacts that the attachment of human and animal pathogens on microplastic may have. Here we synthesise current knowledge regarding these distinct microplastic-associated bacterial communities and microplastic uptake pathways into bivalves, and discuss whether they represent a human and animal health threat, highlighting the outstanding questions critical to our understanding of this potential risk to food safety., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Microplastics (<5 mm) exhibit intrinsic features such as density, hydrophobic surface, or high surface/volume ratio, that are known to promote microbial colonization and biofilm formation in marine ecosystems. Yet, a relatively low number of studies have investigated the nature of microplastic associated bacterial communities in coastal ecosystems and the potential factors influencing their composition and structure. Here, we characterized microplastics collected in the Bay of Brest by manual sorting followed by Raman spectroscopy and studied their associated bacterial assemblages using 16S amplicon high-throughput sequencing. Our methodology allowed discriminating polymer type (polyethylene, polypropylene and polystyrene) within small size ranges (0.3-1 vs. 1-2 vs. 2-5 mm) of microplastics collected. Data showed high species richness and diversity on microplastics compared to surrounding seawater samples encompassing both free living and particle attached bacteria. Even though a high proportion of operational taxonomic units (OTU; 94 ± 4%) was shared among all plastic polymers, polystyrene fragments exhibited distinct bacterial assemblages as compared to polyethylene and polypropylene samples. No effect of microplastic size was revealed regardless of polymer type, site and date of collection. The Vibrio genus was commonly detected in the microplastic fraction and specific PCR were performed to determine the presence of potentially pathogenic Vibrio strains (namely V. aestuarianus and the V. splendidus polyphyletic group). V. splendidus related species harboring putative oyster pathogens were detected on most microplastic pools (77%) emphasizing the need of further research to understand the role of microplastics on pathogen population transport and ultimate disease emergence., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

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

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

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

Con el fin de determinar la calidad bacteriológica de los productos pesqueros en las diferentes etapas de comercialización, desde marzo del 2004 y hasta febrero del 2006, recolectamos muestras mensuales y realizamos análisis microbiológicos para determinar coliformes totales (CT), coliformes fecales (CF), Escherichia coli, recuento total aerobio (RTA), Salmonella sp., Staphylococcus aureus, Vibrio cholerae y Vibrio parahaemolyticus en la piel, el vientre y la carne de los productos. Hubo diferencias en la cantidad de CT encontrada entre las diferentes zonas corporales muestreadas, siendo la piel la zona con mayor conteo. En el 11% de las muestras identificamos E. coli y el 2.5% de los recuentos totales superaron los límites máximos aceptados. Salmonella sp., V. cholerae y V. parahaemolyticus estuvieron ausentes, mientras que sólo el 1.3% de las muestras fueron positivas para S. aureus.Bacteriological load of the fishes Cynoscion squamipinnis and Lutjanus gutattus in the marketing chain, Costa Rica. To determine the bacteriological quality of fishery products in the different stages from commercialization, monthly samples were taken during March 2004 and February 2006 from a Costa Rica marketing chain. Microbiological analyses were made to determine total coliforms (CT), faecal coliforms (CF), Escherichia coli (EC), aerobic total count (RTA), Salmonella sp., Staphylococcus aureus, Vibrio cholerae and Vibrio parahaemolyticus. Three body zones were analyzed: skin, belly and muscle. There were differences in the amount of CT between parts: skin had the highest counts, 11% of samples were identified as E. coli. and 2.5% of total counts were higher than the legal limit. Only 1.3% of the samples were S. aureus-positive. Salmonella sp., V. cholerae and V. parahaemolyticus were absent. Rev. Biol. Trop. 57 (1-2): 45-52. Epub 2009 June 30.

The Red Sea has a unique geography and ecosystem and its shores are very rich in mangrove, macro-algae and coral reefs. Different sources of pollution are affecting the Red Sea shores and waters which impacts biological life including microbial life. We assessed the effects of industrialization, along the Egyptian Red Sea coast in eight coastal sites and two lakes, on microbial life. The bacterial community in sediment samples was analyzed using bacterial 16S rDNApyrosequencing of V6-V4 hypervariable regions. Taxonomical assignment of 131,402 significant reads to major bacterial taxa revealed five main bacterial phyla dominating the sampled Red Sea sites. This includes Proteobacteria (68%), Firmicutes (13%), Fusobacteria (12%), Bacteriodetes (6%) and Spirochetes (0.03%). Further analysis revealed distinct bacterial consortium formed mainly of: 1) marine Vibrio's- suggesting a "Marine Vibrio phenomenon" 2) potential human pathogens and 3) oil-degrading bacteria. We discuss a distinct microbial consortium in Solar Lake West near Taba/Eilat and Saline Lake in Ras Muhammad; revealing the highest abundance of human pathogens versus no pathogens, respectively. Our results draw attention to the affects of industrialization on the Red Sea, and suggest further analysis to overcome hazardous affects on the impacted sites. [ABSTRACT FROM AUTHOR]

To determine the bacteriological quality of fishery products in the different stages from commercialization, monthly samples were taken during March 2004 and February 2006 from a Costa Rica marketing chain. Microbiological analyses were made to determine total coliforms (CT), faecal coliforms (CF), Escherichia coil (EC), aerobic total count (RTA), Salmonella sp., Staphylococcus aureus, Vibrio cholerae and Vibrio parahaemolyticus. Three body zones were analyzed: skin, belly and muscle. There were differences in the amount of CT between parts: skin had the highest counts, 11% of samples were identified as E. coli, and 2.5% of total counts were higher than the legal limit. Only 1.3% of the samples were S. aureus-positive. Salmonella sp., V cholerae and V. parahaemolyticus were absent. [ABSTRACT FROM AUTHOR]

Surveys for bacteriological analysis of larval samples to isolate the associated vibrios were carried out during 1985–1992, 2001 and 2002 in three different hatcheries located on the southwest coast of India. Vibrio isolates were examined for their species diversity, virulence based on haemolysis in prawn blood agar, lipolysis, proteolysis and chitinolysis and antibiotic sensitivity. Vibrio cholerae was the predominant species in the apparently healthy larval samples, whereas V. alginolyticus and V. vulnificus dominated during disease and morbidity. No correlation was found between the hydrolytic properties and haemolytic activity of the vibrios associated with the larvae. All isolates were resistant to erythromycin and resistance to oxytetracycline, ampicillin and streptomycin sulphate was prevalent among the larger section of the Vibrio population. This suggested that antibiotic application may not be of much use to protect the larvae from vibriosis. This is the first report on the diversity of Vibrio species associated with Macrobrachium rosenbergii larvae and their virulence characteristics based on haemolysis in prawn blood agar. [ABSTRACT FROM AUTHOR]

Abstract: This study was carried out seasonally, throughout a year, to evaluate the filtering activity on bacteria of Mytilus galloprovincialis. Six microbiological parameters were researched in the water and mussels samples collected along the coastal area of the Northern Ionian Sea in three stations, S. Vito, Lido Gandoli and Lido Silvana. We detected the densities of culturable heterotrophic bacteria by spread plate on Marine Agar, total culturable bacteria at 37°C on Plate Count Agar and vibrios abundance on thiosulphate-citrate-bile-sucrose-salt (TCBS) agar. Total and fecal coliforms as well as fecal streptococci were determined by the Most Probable Number. Bacterial concentrations at 20 and 37°C as well as vibrios concentrations were higher in the mussel samples compared to the corresponding seawater throughout the year. The results obtained could contribute to improve the information relatively either to the natural processes existing between bacteria and mussels or to the risk of human infections related to the consumption of mussels. [Copyright &y& Elsevier]