Our studies focus on the genetics and regulation of iron acquisition systems and other virulence factors of the intestinal pathogens Shigella flexneri and Vibrio cholerae. Our work combines biochemistry and genetics to determine how the essential metals iron and manganese are transported and utilized in V. cholerae and S. flexneri. Iron transport systems are of particular interest to us because iron acquisition in the human host is critical to microbial virulence. Additionally, we use in vitro models combined with genetic analyses to determine the role of host lipids and carbon metabolism in the pathogenesis of S. flexneri. And we are intested in exploring the environmental regulation of critical virulence factors by the RNA binding protein CsrA in V. cholerae.