Microbial iron acquisition system

Microbial iron acquisition systems are specialized mechanisms employed by bacteria and fungi to sequester iron from their environment, a process essential for their growth and virulence (Saha et al., 2013). In the context of human infection, pathogens must overcome "nutritional immunity," where the host actively sequesters iron using proteins like transferrin and lactoferrin (Nairz et al., 2010). These microbial systems primarily utilize siderophores—small, high-affinity iron-chelating ligands—that are secreted, bind ferric iron, and are subsequently recognized by specific cell-surface receptors for internalization (Kramer et al., 2020). Therapeutic targeting of these systems often involves the "Trojan horse" approach, where antibiotics are conjugated to siderophore mimetics to exploit active transport pathways, effectively bypassing traditional resistance mechanisms like porin loss (Zhanel et al., 2019). Cefiderocol is a prominent example of a siderophore-conjugated antibiotic currently used to treat multi-drug resistant Gram-negative infections by targeting these uptake systems (Zhanel et al., 2019). Beyond transport, research also focuses on inhibiting siderophore biosynthesis or using iron analogs like gallium to disrupt microbial metabolism (Saha et al., 2013). These systems are also critical for the formation of biofilms, making them a target for anti-virulence strategies (Nairz et al., 2010). Because these systems are often specific to the pathogen, they offer a pathway for narrow-spectrum antimicrobial development (Kramer et al., 2020).

Other names

Siderophore-mediated iron uptake systemsBacterial iron transport systemsHeme acquisition systemsTonB-dependent transport systemsIron-uptake machinery

Trojan horse transport facilitation via siderophore-mimetic conjugation; Iron sequestration; Competitive inhibition of iron-dependent metabolic enzymes; Inhibition of siderophore biosynthesis enzymes.