Heme binding and transport by the Staphylococcus aureus Isd system

Staphylococcus aureus is a bacterial pathogen that is of considerable medical concern. Though it normally lives externally on humans or animals, S. aureus causes problems when it is introduced into breaks in skin or mucosal surfaces, enabling it to invade the surrounding tissues and move into the blood stream. S. aureus poses an especially great threat in the hospital setting where it is one of the most commonly acquired bacterial infections and a serious cause of disease and death. The emergence of multidrug-resistant “superbugs” has highlighted the potential threat S. aureus poses in the health care system. There is an imperative need for new means of inhibiting the growth of S. aureus. As in many other organisms, iron is required for growth in S. aureus – an element that the bacteria must either extract or scavenge from within the human system. The majority of iron in the human body is found in heme, and many other organisms have evolved to utilize heme as an iron source. Recently, S. aureus was also shown to preferentially use heme-iron in early growth, but little is known about its heme uptake mechanism. Jason Grigg is exploring the function and structure of a set of four cell surface heme binding proteins found on S. aureus. By describing how the bacteria grows by extracting iron from its host, this research may lead to new ways to “starve” the bacteria and inhibit its pathogenesis.