TY - JOUR T1 - Adaptation of <em>Staphylococcus saprophyticus</em> at the host-pathogen interface JF - bioRxiv DO - 10.1101/136556 SP - 136556 AU - Tatum D. Mortimer AU - Douglas S. Annis AU - Mary B. O’Neill AU - Lindsey L. Bohr AU - Tracy M. Smith AU - Hendrik N. Poinar AU - Deane F. Mosher AU - Caitlin S. Pepperell Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/05/10/136556.abstract N2 - Human-pathogenic bacteria are found in a variety of niches, including free-living, zoonotic, and microbiome environments. Identifying bacterial adaptions that enable invasive disease is an important means of gaining insight into the molecular basis of pathogenesis and understanding pathogen emergence. Staphylococcus saprophyticus, a leading cause of urinary tract infections, can be found in the environment, food, animals, and the human microbiome. We identified a selective sweep in the gene encoding the Aas adhesin, a key virulence factor. The mutation under selection affects binding to host fibronectin, and we hypothesize that it facilitates colonization of the urinary tract, an environment where bacteria are subject to strong shearing forces. The mutation appears to have enabled emergence and expansion of a human pathogenic lineage of S. saprophyticus. These results demonstrate the power of evolutionary genomic approaches in discovering the genetic basis of virulence and emphasize the pleiotropy and adaptability of bacteria occupying diverse niches. ER -