Acinetobacter baumannii outer membrane (Ab OM)

The Acinetobacter baumannii outer membrane is a specialized asymmetric lipid bilayer that serves as the primary interface between the bacterium and its environment, providing a robust physical barrier against host immune defenses and antibiotics (PubMed: 31501234). The outer leaflet is predominantly composed of lipopolysaccharide (LPS), which is essential for membrane stability and serves as a key virulence factor (NIH: PMC6471137). This structure is embedded with various proteins, including porins like OmpA and CarO, which regulate the influx of nutrients and drugs, and efflux systems that contribute to multi-drug resistance (PubMed: 29439114). Because of its role in antibiotic exclusion, the outer membrane is a major focus for drug development; for instance, polymyxins target the LPS to disrupt membrane integrity, while newer agents like Zosurabalpin inhibit the LptB2FGC complex to prevent LPS transport to the surface (Nature: 10.1038/s41586-023-06873-0). Targeting this structure is a critical strategy in addressing carbapenem-resistant A. baumannii (CRAB) infections, which are associated with high mortality rates in clinical settings.

Other names

Acinetobacter baumannii cell envelopeGram-negative outer membraneBacterial outer membrane

Drugs targeting the outer membrane typically act by disrupting the lipid bilayer (e.g., polymyxins), inhibiting the transport of lipopolysaccharide (LPS) to the surface (e.g., Zosurabalpin), or utilizing specialized transport systems like siderophore-mediated uptake (e.g., cefiderocol) to bypass the barrier.