Flavobacterium turcicum sp. nov. and Flavobacterium kayseriense sp. nov. isolated from farmed rainbow trout in Turkey.

During a study on culturable microorganisms from fish farms, four yellow-pigmented gram negative, rod shaped isolates, F-47, F-339, F-380 and F-400, were recovered from rainbow trout samples exhibiting clinical signs. Based on 16S rRNA gene sequence analysis, the strains were identified as members of the genus Flavobacterium. Strains F-47 and F-380 shared the highest 16S rRNA gene sequence identity level of 97.6% with the type strain of Flavobacterium frigoris DSM 15719 while strains F-339 and F-400 shared the highest identity level of 97.6% with the type strain of F. caseinilyticum AT-3-2. A polyphasic taxonomic approach including phenotypic and genomic characterization as well as whole-cell MALDI-TOF mass spectrometry analyses was employed to ascertain the taxonomic position of the strains within the genus Flavobacterium. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses between strains F-47, F-339 and their close neighbours F. frigoris DSM 15719 and F. caseinilyticum AT-3-2, respectively, confirmed that both strains represent novel species in the genus Flavobacterium. The DNA G+C contents of the strains F-47 and F-339 are 34.3% and 35.3%, respectively. It can be concluded on the basis of polyphasic characterization as well as pairwise genome comparisons that the strains F-47 and F-339 represent two novel species within the genus Flavobacterium, for which Flavobacterium kayseriense sp. nov. F-47 (=JCM 34195=KCTC 82255) and Flavobacterium turcicum sp. nov. F-339 (=JCM 34202=KCTC 82262) are proposed, respectively.