Extracellular polymeric substances (EPS) (EPS)

Extracellular polymeric substances (EPS) constitute the self-produced, complex matrix that encases bacterial cells within a biofilm, often representing up to 90% of the total organic matter [1.1.3, 1.2.2]. This matrix is primarily composed of polysaccharides, proteins, extracellular DNA (eDNA), and lipids, which together provide structural stability and facilitate adhesion to surfaces [1.2.3, 1.4.1]. EPS serves as a formidable physical and chemical barrier, protecting the embedded bacteria from host immune cells and significantly reducing the penetration of antimicrobial agents [1.2.4, 1.4.3]. This protective role is a major factor in the development of chronic, recalcitrant infections, such as those found in cystic fibrosis, chronic wounds, and on indwelling medical devices [1.2.1, 1.3.2]. Therapeutic interventions targeting EPS focus on degrading its components—using enzymes like dornase alfa for eDNA or glycoside hydrolases for polysaccharides—or inhibiting its synthesis to disrupt biofilm integrity [1.3.2, 1.3.5]. By weakening the EPS matrix, these strategies aim to restore the efficacy of conventional antibiotics and enhance the host's ability to clear the infection [1.3.2, 1.3.3].

Other names

Biofilm matrixExopolysaccharidesExtracellular matrix (bacterial)Slime layerBiopolymer matrix

Drugs targeting EPS act through the enzymatic degradation of matrix components such as eDNA, polysaccharides, and proteins, or by inhibiting the synthesis and assembly of these polymers [1.3.1, 1.3.2, 1.3.3]. Additionally, chelating agents like EDTA disrupt the matrix by removing divalent cations (e.g., Ca2+, Mg2+) that provide structural cross-linking and stability [1.1.2, 1.3.1]. Some antibiotics, such as macrolides, can also inhibit the production of specific EPS components like alginate [1.3.1].