Conserved genes in a path from commensalism to pathogenicity: comparative phylogenetic profiles of Staphylococcus epidermidis RP62A and ATCC12228

Background Staphylococcus epidermidis, long regarded as an innocuous commensal bacterium of the human skin, is the most frequent cause of nosocomial infections associated with implanted medical devices. This conditional pathogen provides a model of choice to study genome landmarks correlated with the transition between commensalism and pathogenicity. Traditional investigations stress differences in gene content. We focused on conserved genes that have accumulated small mutation differences during the transition.