Outer membrane acinetobactin receptor (BauA) (BauA)

The Outer membrane acinetobactin receptor (BauA) is a TonB-dependent protein that serves as the primary gateway for the uptake of the siderophore acinetobactin in the Gram-negative pathogen Acinetobacter baumannii (1, 9). Iron is an essential micronutrient for bacterial proliferation, and because the human host actively sequesters iron to restrict pathogen growth, A. baumannii secretes acinetobactin to scavenge it from host proteins like transferrin and lactoferrin (5, 14, 16). The resulting ferric-acinetobactin complex is recognized with high affinity by BauA and transported across the outer membrane into the periplasm, a process essential for the bacterium's survival and virulence in the host (1, 2, 4). Due to its critical role in pathogenesis and its high conservation across multidrug-resistant clinical isolates, BauA is a major target for novel antimicrobial strategies (3, 7). Drug development efforts utilize a "Trojan horse" approach where antibiotics, such as the approved siderophore-cephalosporin Cefiderocol or various experimental conjugates, are chemically linked to siderophore-like moieties to hijack the BauA and related iron-uptake systems for entry (2, 8, 12, 13). Furthermore, BauA is actively being investigated as a potential vaccine candidate, with studies demonstrating that immunization can elicit protective antibodies and reduce bacterial load in murine sepsis models (3, 15).

Other names

BauA proteinFerriacinetobactin receptorAcinetobactin receptorBaumannii acinetobactin utilization A

Siderophore-mediated active transport (Trojan horse strategy) which exploits bacterial iron uptake systems to deliver antimicrobial agents directly into the periplasm or cytoplasm; potential inhibition of iron acquisition through receptor neutralization.