Oceanivirga salmonicida gen. nov., sp. nov., a member of the leptotrichiaceae isolated from atlantic salmon (salmo salar)

Abstract

A pleomorphic, Gram-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was originally isolated in 1992 from moribund, seawater farmed Atlantic salmon with multifocal tissue necrosis. Strain AVG 2115(T) displayed considerable similarities with Streptobacillus moniliformis, one of the two etiological agents of rat bite fever, and has been stored as Streptobacillus sp. NCIMB 703044(T). On the basis of 16S rRNA gene sequence analyses, this strain displayed >99 % sequence similarities with uncultured bacterial clones from the digestive tracts of marine mammals, followed by Sneathia sanguinegens CCUG 41628(T) (92.7 %), 'Sneathia amnii' Sn35 (92.5 %), Caviibacter abscessus CCUG 39713(T) (92.2 %), Streptobacillus rattiOGS16(T) (91.3 %), Streptobacillus notomytis AHL 370-1(T) (91.2 %), S. moniliformis DSM 12112(T) (91.0 %), Streptobacillus fells 131000547(T) (90.9 %) and Streptobacillus hongkongensis DSM 26322(T) (89.7 %). Sequence similarities to all other taxa were below 89 %. Phylogenetic analysis for strain NCIMB 703044(T) revealed highly similar results for gyrB, groEL and recA nucleotide and deduced amino acid sequence analyses independent of the employed treeing method. Average nucleotide identities (ANI) for complete genomes ranged from 66.00 % to 72.08 % between strain NCIMB 703044(T) and the type strains of Sebaldella termitidis, Leptotrichia buccalis, Streptobacillus moniliformis, Sneathia sanguinegens and Caviibacter abscessus. Chemotaxonomic and physiological data of strain NCIMB 703044(t) were in congruence with closely related members of the family Leptotrichiaceae, represented by highly similar enzyme profiles and fatty acid patterns. MALDI-TOF MS analysis was capable to clearly discriminate strain NCIMB 703044(T) from all currently described taxa of the family Leptotrichiaceae. On the basis of these data we propose the novel taxon Oceanivirga salmonicida gen. nov. sp. nov. with the type strain AVG 2115(T) (= NCIMB 7030441(T)) (=DSM 101867(T)). The G+C content is 25.40 %, genome size is 1.77 Mbp.