Bacterial cell wall and outer membrane

The bacterial cell wall and outer membrane constitute the essential protective envelope of bacteria, providing structural integrity and protection against osmotic lysis (Silhavy et al., 2010, Cold Spring Harb Perspect Biol). The cell wall is primarily composed of peptidoglycan, a mesh-like polymer of sugars and amino acids, which is significantly thicker in Gram-positive bacteria than in Gram-negative species (Egan et al., 2020, Nat Rev Microbiol). Gram-negative bacteria are further characterized by an outer membrane containing lipopolysaccharides, which serves as a selective permeability barrier against toxic molecules, including many antibiotics (Nikaido, 2003, Microbiol Mol Biol Rev). These structures are critical for bacterial viability, making them the primary targets for several classes of antibiotics, such as beta-lactams, which inhibit peptidoglycan cross-linking, and polymyxins, which disrupt the outer membrane (Bush & Bradford, 2016, Cold Spring Harb Perspect Med). Targeting the cell envelope is a cornerstone of treating bacterial infections, although the emergence of resistance mechanisms, such as modified penicillin-binding proteins or altered outer membrane porins, poses a significant clinical challenge (Blair et al., 2015, Nat Rev Microbiol).

Other names

Bacterial cell envelopePeptidoglycan layerMureinLipopolysaccharide layerBacterial membrane

Inhibition of peptidoglycan biosynthesis (e.g., transpeptidation), inhibition of cell wall precursor transport, disruption of outer membrane integrity via lipid A binding, and depolarization of the cytoplasmic membrane.