Polysaccharide-Rich Biofilms in Pathogenic Microorganisms: Molecular Architecture, Functional Roles, and Innovative Therapeutic Strategies

Abstract

Microbial biofilms are complex communities of microorganisms attached to surfaces and surrounded by an extracellular matrix made up of polysaccharides, proteins, and other biopolymers, which contribute to their structural stability and function. Polysaccharides play a central role in biofilm formation, providing adhesion, cohesion, and protection against environmental stress, antibiotics, and host immune defenses. This review explores the biosynthesis and molecular diversity of microbial exopolysaccharides (EPS), focusing on their functional roles in biofilm architecture and pathogenicity. It discusses the different biosynthetic pathways that produce EPS, such as the Wzx/Wzy-dependent, ABC transporter-dependent, and synthase-dependent pathways. The review also highlights the structural diversity of key polysaccharides like alginate, Psl, Pel, and PNAG, and their contribution to biofilm stability and antibiotic resistance. Additionally, emerging therapeutic strategies targeting the biofilm matrix, including enzymatic degradation, antibiofilm agents, and quorum sensing inhibition, are explored as potential approaches to combat biofilm-associated infections. These strategies aim to disrupt the EPS matrix, enhance antibiotic penetration, and improve infection control, especially in chronic and multidrug-resistant infections caused by pathogens like Pseudomonas aeruginosa and Staphylococcus aureus.