Schematic of ESS gene clusters in Gram-positive bacteria. Comparison of the S. aureus ESS locus with Listeria monocytogenes (strain EGD-e ), Bacillus cereus “cytotoxicus” (strain NVH391-98) and B. subtilis (subsp. subtilis strain 168) . Genes sharing sequence homology are depicted with the same color. Proteins with defined conserved domains are indicated as follows: WXG100 family of proteins (red), FtsK SpoIIIE-like ATPases (yellow), Cluster of Orthologous Groups of proteins COG5444 (dark blue), COG4499 (black) and proteins with a Domain of Unknown Function DUF600 (light blue). Dashed lines between blocks of genes indicate that the genes are not found in close proximity but elsewhere on the same chromosome. The nomenclature for the S. aureus cluster has been described . The genetic organization is conserved in S. aureus strains. Gene names for B. subtilis (subsp. Subtilis strain 168) are annotated as described in the National Center for Biotechnology Information databank.