ABC transporter; part of the gene cluster that mediates the biosynthesis of hydroxamate-containing siderophores that play a critical role in virulence via intracellular iron acquisition during macrophage infection (PubMed:18404210). Probably involved in the excretion of the extracellular siderophores (PubMed:18404210). Expression is induced during iron deprivation (PubMed:18404210). Belongs to the ABC transporter superfamily. ABCB family. Multidrug resistance exporter (TC 3.A.1.201) subfamily.