Legionella septentrionalis sp. nov., isolated from aquatic environments in the northern PR China

Four strains (km711 T , km714, km542 and km524), representing a novel Legionella species, were isolated from aquatic environments in northern PR China. Cells were Gram-stain-negative, rod-shaped, microaerobic, motile and growth depended on l -cysteine. They grew at 25‒42 °C (optimum, 35‒37 °C) and could tolerate up to 1.5 % (w/v) NaCl (optimum, 0.5 %). The major fatty acids (>5 %) of the type strain km711 T were C 17 : 0 anteiso, C 15 : 0 anteiso, iso-C 16 : 0 and C 16 : 1  ω 7 c and/or iso-C 15 : 0 2OH. The pairwise comparison values were <96.1 % for 16S rRNA gene sequences, 23.3‒28.7 % interspecies variation for mip gene sequences, <93.6 % average nucleotide identity and <72.8 % average amino acid identity between these four strains and related type strains within the genus Legionella . The phylogenetic tree based on the four concatenated genes (16S rRNA, mip , rpoB and rnpB ) and protein-concatamer tree based on concatenation of 21 protein markers both revealed that these four strains formed a separate phylogenetic branch cluster within the genus Legionella . The results of phenotypic and genotypic features suggest that these four strains represent a novel species of the genus Legionella , for which the name Legionella septentrionalis sp. nov. is proposed (type strain km711 T =KCTC 15655 T =NBRC 113219 T ).