Iron is one such nutrient that is vital to the host-S. aureus
interaction [6]. As a cofactor in heme moieties, it functions in
electron transport as well as enzymatic roles in diverse processes of
S. aureus [7]. In host system, the majority of iron is bound by
intracellular iron-binding proteins, and restricting the access of
iron is a common strategy to limit S. aureus growth. In order to grow
within host, S. aureus must liberate intracellular iron, such as hemeiron,
and compete with host iron-sequestering proteins. The primary
S. aureus heme-uptake system is termed the iron-regulated
surface determinant (Isd) system [5,8].