Bacterial outer membrane permeability barrier

The bacterial outer membrane permeability barrier is a distinctive feature of Gram-negative bacteria, functioning as an asymmetric lipid bilayer comprised of phospholipids (inner leaflet), lipopolysaccharide (outer leaflet), outer membrane proteins (porins), and lipoproteins[2][3][5]. This barrier serves to protect bacteria from hostile elements in their environment by preventing the entry of toxic substances, including many antibiotics, while still permitting selective uptake of nutrients through porins. Manipulation of this barrier, usually by disrupting its structure with compounds such as polymyxins or by inhibiting efflux pumps, is a recognized pharmacological strategy to increase bacterial susceptibility to antibiotics. However, the permeability barrier itself is not a single molecular target, but an emergent property of the membrane’s overall composition and organization[2][3][5][6].

Other names

Outer membrane permeabilityOM permeabilityGram-negative bacterial outer membrane

Disruption or destabilization of outer membrane structure (e.g., polymyxins bind LPS, displacing stabilizing cations, leading to increased permeability and cell death) Enhancement of permeability to allow entry of otherwise excluded antibiotics