Vibrio caribbeanicus sp. nov., isolated from the marine sponge Scleritoderma cyanea

Abstract

A Gram-negative, oxidase-positive, catalase-negative, facultatively anaerobic, motile, curved rod-shaped bacterium, strain N384T, was isolated from a marine sponge (Scleritoderma cyanea; phylum Porifera) collected from a depth of 795 feet (242 m) off the west coast of Curaçao. On the basis of 16S rRNA gene sequencing, strain N384T was shown to belong to the genus Vibrio , most closely related to Vibrio brasiliensis LMG 20546T (98.8 % similarity), Vibrio nigripulchritudo ATCC 27043T (98.5 %), Vibrio tubiashii ATCC 19109T (98.6 %) and V. sinaloensis DSM 21326T (98.2 %). The DNA G+C content of strain N384T was 41.6 mol%. An analysis of concatenated sequences of five genes (gyrB, rpoA, pyrH, mreB and ftsZ; 4068 bp) demonstrated a clear separation between strain N384T and its closest neighbours and clustered strain N384T into the ‘Orientalis’ clade of vibrios. Phenotypically, the novel species belonged to the arginine dihydrolase-positive, lysine decarboxylase- and ornithine decarboxylase-negative (A+/L−/O−) cluster. The novel species was also differentiated on the basis of fatty acid composition, specifically that the proportions of iso-C13 : 0, iso-C15 : 0, C15 : 0, iso-C16 : 0, C16 : 0, iso-C17 : 0, C17 : 1ω8c and C17 : 0 were significantly different from those found in V. brasiliensis and V. sinaloensis . The results of DNA–DNA hybridization, average nucleotide identity and physiological and biochemical tests further allowed differentiation of this strain from other described species of the genus Vibrio . Collectively, these findings confirm that strain N384T represents a novel Vibrio species, for which the name Vibrio caribbeanicus sp. nov. is proposed, with the type strain N384T ( = ATCC BAA-2122T = DSM 23640T).