Strain TB1-E2-13T was isolated from water collected from the Tidal Basin in Washington, D.C., USA, due to the bright purple colour of its colonies, and was taxonomically evaluated with a polyphasic approach. Comparison of a partial 16S rRNA gene sequence found that strain TB1-E2-13T was most similar to species in the Janthinobacterium genus. For more precise taxonomic inference, a phylogenomic analysis was conducted and indicated that strain TB1-E2-13T was most closely related to Janthinobacterium lividum, 'Janthinobacterium kumbetense', Janthinobacterium rivuli and Janthinobacterium violaceinigrum. Analyses of genomic indices found that pairwise comparisons between strain TB1-E2-13T and other members of the Janthinobacterium genus returned values below the threshold of species novelty. Based on a polyphasic characterization and identifying differences in genomic and taxonomic data, strain TB1-E2-13T represents a novel species, for which the name Janthinobacterium aestuarii sp. nov. is proposed. The type strain is TB1-E2-13T (=ATCC TSD-339T=JCM 36076T).
Keywords: Janthinobacterium; novel species; tidal basin; violacein; water.