Photobacterium swingsii sp. nov., isolated from marine organisms

Six Gram-negative coccobacilli were isolated from Pacific oysters (Crassostrea gigas) from Mexico and haemolymph of spider crabs (Maja brachydactyla) from Spain. All of the isolates grew as small green colonies on thiosulphate-citrate-bile salts-sucrose (TCBS) agar and were facultatively anaerobic, oxidase-positive and sensitive to the vibriostatic agent O/129. Repetitive palindromic PCR analysis revealed a high degree of genomic homogeneity among the isolates. Several phenotypic traits differentiated the isolates from the type strains of species of the genus Photobacterium. DNA-DNA relatedness between two representative isolates and their closest phylogenetic neighbours by 16S rRNA gene sequence similarity, Photobacterium aplysiae CAIM 14(T) and Photobacterium frigidiphilum CAIM 20(T), was 44.01-53.85 %. We propose a novel species of the genus Photobacterium to accommodate the six isolates, with the name Photobacterium swingsii sp. nov. The type strain is CAIM 1393(T) (=CECT 7576(T)).