Vibrio gigantis sp. nov., isolated from the haemolymph of cultured oysters (Crassostrea gigas).

Polyphasic analysis of four new Vibrio isolates originating from the haemolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on DNA gyrase subunit B (gyrB), RNA polymerase sigma70 factor (rpoD), replication origin-binding protein (rctB) and transmembrane regulatory protein (toxR) genes, fluorescent amplified fragment length polymorphism and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed that these new isolates should be accommodated in a novel species, Vibrio gigantis sp. nov. Phenotypic features that differentiate V. gigantis from other known Vibrio species include arginine dihydrolase, gelatinase and beta-galactosidase activities, NO(2) production, growth at 35 degrees C, and utilization of sucrose, melibiose, amygdalin, glycerol, galactose, starch and glycogen. The type strain is LGP 13T (=LMG 22741T=CIP 108656T).