Bacterial membranes, biofilm matrices, and mucus glycoprotein networks

Bacterial membranes, biofilm matrices, and mucus glycoprotein networks constitute the primary physical and chemical barriers that sequester pathogens and impede the delivery of antimicrobial agents. Bacterial membranes, particularly the outer membrane of Gram-negative bacteria, serve as a primary defense against hydrophobic molecules and large antibiotics (Breijyeh et al., 2020, Microorganisms). Biofilm matrices are composed of extracellular polymeric substances (EPS), including polysaccharides, proteins, and extracellular DNA (eDNA), which provide structural stability and create a protective microenvironment that fosters antibiotic resistance (Flemming & Wingender, 2010, Nature Reviews Microbiology). Mucus glycoprotein networks, or mucins, form a dense, viscoelastic barrier on mucosal surfaces that traps particles and limits the diffusion of drugs to the underlying epithelium (Wagner et al., 2018, Nature Reviews Materials). Therapeutic strategies targeting these barriers involve the use of membrane-active peptides, matrix-degrading enzymes like DNase, and mucolytic agents to improve drug bioavailability and therapeutic outcomes in chronic infections such as cystic fibrosis and wound biofilms. Understanding the interplay between these barriers is crucial for developing effective treatments for chronic and multi-drug resistant infections.

Other names

Bacterial cell envelopeExtracellular polymeric substancesEPSMucin networksBiological barriersMicrobial biofilms

Drugs targeting these structures act by disrupting the integrity of the bacterial lipid bilayer, enzymatically degrading the extracellular polymeric substances (EPS) within biofilms, or reducing the viscoelasticity of mucus networks through the cleavage of disulfide bonds or extracellular DNA to enhance drug penetration and pathogen clearance.