Strain-level taxonomic differentiation of bacteria using 16S databases (SILVA, RDP, Riken, HOMD, etc.) is typically not possible regardless of how many reads are in the database, because the 16S gene does not contain sufficient variability to differentiate many species/strains. Mapping to 16S databases will typically assign taxonomy at the genus level at best because the information about the spacer-region sequence is not included. For the same reason, identification of novel strains is typically not possible. The spacer-region sequences between the genes are a rich source of variability crucial for differentiating closely related bacterial strains. The Athena database contains contiguous 16S-23S gene sequences from comprehensive, integrated, non-redundant, well-annotated genomes allowing strain level identification.