Vibrio marinisediminis sp. nov., Isolated from Marine Sediment

A novel Gram-stain-negative, facultative anaerobic, motile bacterium, designated as 404^T, was isolated from a marine sediment sample in the Bohai Gulf, China. Growth was observed at 10-35 °C (optimum, 20-25 °C) and in the presence of 1.0-6.0% (w/v) NaCl (optimum, 1.0-3.0%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain 404^T belonged to the genus Vibrio, showing the highest sequence similarity to Vibrio renipiscarius KCTC 42287^T (97.6%). The draft genome is 4.5 Mb in length, containing 4278 protein-coding genes, 60 tRNA genes and 9 rRNA genes, and DNA G+C content is 44.1 mol%. Strain 404^T contains phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, and phospholipid as the main polar lipids, and the predominant quinone is ubiquinone Q-8. The major cellular fatty acids (>8.0%) are C_16 : 1ω6c and/or C_16 : 1ω7c, C_16 : 0, C_18 : 1ω6c and/or C_18 : 1ω7c. Strain 404^T shows some typical characteristics among the members of genus Vibrio, while it can be clearly distinguished from the closely related type strains through genome analysis (average nucleotide identity and digital DNA-DNA hybridization values), fatty acid composition and a series of physiological and biochemical characteristics. On the basis of the polyphasic analysis, strain 404^T is considered to represent a novel species of the genus Vibrio, for which the name Vibrio marinisediminis sp. nov., is proposed. The type strain is 404^T (= MCCC 1H00367^T = KCTC 62958^T).

Marine aggregates in North Atlantic coast: Microbial characteristics and potential interactions with farmed Atlantic salmon (Salmo salar)

Microbial contamination of aggregates collected near an Atlantic salmon farm, in the Cherbourg roadstead, was followed monthly over one year to study the dynamics of Vibrio spp. and explore their impact on farmed fish. Salmon state of health was followed through blood and histopathological analyses. Vibrio were systematically found in aggregates with particularly high concentration in August. The Splendidus clade was strongly dominant in aggregates as well as in gills, and an increase in Vibrio diversity was observed in summer and autumn. Results did not demonstrate that aggregates directly impact the bacterial community of gills, but they suggested an aggregates-gills interaction. Gill contamination was correlated with water temperature and probably impacted by amoebae. Vibrio renipiscarius and Vibrio toranzoniae were isolated in North Atlantic for the first time. A better understanding of the interaction between marine aggregates, Vibrio spp. and fish is essential to improve salmon cage farming.