Dyadobacter helix sp. nov. and Dyadobacter linearis sp. nov., from drinking water

The purpose of this study is to better characterize and complete the classification of two bacterial strains, CECT 9275^T and CECT 9623^T, isolated from drinking water systems and affiliated to the genus Dyadobacter by partial 16S rRNA gene sequence comparison. Hence, we report here the phenotypic, genomic and phylogenetic characterization performed on these strains. Both strains grow on R2A agar forming mucous, bright yellow colonies, developing at 26 °C in 48 h. They produce flexirubin and are oxidase and catalase positive, mesophilic and non-halophilic. The cells of strain CECT 9275^T are curved rods mainly associated in pairs, forming nearly closed rings or resembling the shape of the number three, to long spirals resembling a corkscrew. Its draft genome has an estimated size of 7.23 Mbp (G+C content 45.4%). Strain CECT 9623^T appeared on wet mounts as straight rods, mostly in pairs, sometimes forming long filaments (up to 20 µm). Its draft genome is shorter, with an estimated size of 6.45 Mbp (G+C content is 46.1%). Overall genome relatedness indexes clearly define them as separate organisms, so based on all the data collected, we propose the species Dyadobacter helix sp. nov. with type strain AB1^T (=CECT 9275^T=LMG 32341^T) and Dyadobacter linearis sp. nov. with type strain AB67^T (=CECT 9623^T=LMG 32342^T).