Bacterial iron transport system

The **bacterial iron transport system** refers to a collection of specialized molecular mechanisms that bacteria use to acquire iron, an essential nutrient often limited in hosts and the environment[1][6][7]. The most widespread and important of these are **siderophore-mediated transport systems**, in which bacteria secrete small, high-affinity iron-chelating molecules (siderophores) to scavenge ferric iron (Fe^3+^), then transport the iron-siderophore complex back into the cell via dedicated receptors (often TonB-dependent outer membrane proteins in Gram-negatives), periplasmic binding proteins, and ATP-dependent ABC transporters[1][6][7]. Other systems directly import ferrous iron (Fe^2+^), some of which involve transporters such as FeoB and MntH[5][7]. These systems are highly redundant, with multiple distinct transporters and receptors even within a single bacterial species, tailored for different iron sources (e.g., heme, ferrichrome, enterobactin, transferrin-bound iron). In pathogens, iron transport systems are essential for virulence, supporting growth and survival within iron-limited environments like host tissues[1][5]. They are considered attractive antimicrobial targets, and some antibiotics—such as cefiderocol—exploit these transport systems to gain entry into bacteria (the "Trojan horse" strategy)[5]. However, "bacterial iron transport system" is not a specific molecular entity but a functionally defined set of diverse molecular complexes, with particular gene and protein names varying by organism and system (e.g., FhuABCD, Fit, FeoB, Fec, etc.)[4][5][6][7].

Other names

Bacterial siderophore-mediated iron uptake systemBacterial ferrous iron transport systemBacterial ferric iron uptake pathwaySiderophore iron transport pathwayBacterial ABC iron transporter

Inhibition of iron uptake (by blocking siderophore receptor or ABC transporter); Trojan horse strategy (antibiotic conjugated to siderophore is imported and kills bacterium); Iron starvation (induced by chelator or competing metal)