Acinetobacter baumannii outer membrane protein (OMP)

Acinetobacter baumannii outer membrane proteins (OMPs) are a diverse group of proteins located in the outer leaflet of the Gram-negative bacterial cell wall, essential for maintaining structural integrity and mediating environmental interactions. These proteins, including major porins like OmpA and CarO, function as channels for nutrient acquisition and are critical virulence factors that facilitate adhesion to host tissues and the development of protective biofilms (Gaddy et al., 2009, PMID: 19139237). OMPs also serve as the primary gateway for many antibiotic classes, such as carbapenems; consequently, the loss or modification of these proteins is a hallmark of multi-drug resistance in clinical settings (Mussi et al., 2005, PMID: 15659488). Specific OMPs like BauA are involved in high-affinity iron uptake systems, which have been successfully exploited by 'Trojan horse' antibiotics like cefiderocol to bypass traditional resistance mechanisms (Shizuchi et al., 2022, PMID: 35194044). Due to their surface exposure and essential roles in bacterial survival, OMPs are currently being targeted for the development of novel small-molecule inhibitors, monoclonal antibodies, and vaccine candidates aimed at treating carbapenem-resistant Acinetobacter baumannii (CRAB) infections (Lee et al., 2017, PMID: 28438973).

Other names

A. baumannii OMPsOuter membrane porinsOuter membrane protein A (OmpA)Carbapenem-associated outer membrane protein (CarO)Acinetobactin utilization protein (BauA)Omp33-36Acinetobacter surface proteins

Drugs interact with these proteins either by utilizing them as entry portals (e.g., carbapenems entering through CarO), exploiting them for active transport via 'Trojan horse' mechanisms (e.g., cefiderocol binding to the iron-siderophore receptor BauA), or by binding to and disrupting the outer membrane stability (e.g., polymyxins interacting with the OMP-LPS complex).