Piscibacter tructae gen. nov., sp. nov., an anaerobic butyrate-producing Fusobacteriaceae bacterium isolated from gut of rainbow trout

A Gram-stain-negative, anaerobic and rod-shaped bacterium was isolated from gut of rainbow trout in Japan. The temperature range for the growth of 9N8^T was 10<i>-</i>30 °C with an optimum at 20 °C. The organism produced acetate and butyrate when grown on AccuDia^™ Gifu Anaerobic Medium broth, Modified. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain 9N8^T was related to the genus <i>Fusobacterium</i> (<92.9% similarity) and formed a distinct phylogenetic lineage from existing genera within the family <i>Fusobacteriaceae</i>. Strain 9N8^T has a genome size of 2.60 Mb. The genomic DNA G+C content was 29.4 mol%. Average amino acid identity values between strain 9N8^T and strains in the family <i>Fusobacteriaceae</i> ranged from 39.2 to 57.5%. The major fatty acids of strain 9N8^T were C_{14 : 0}, C_{16 : 1} ω7c and C_{16 : 0}. On the basis of the morphological, physiological, biochemical and genetic information, a novel genus and species, <i>Piscibacter tructae,</i> is proposed, with 9N8^T (=NBRC 116745^T=DSM 118263^T) as the type strain.