Basics of Biofilm Architecture and Antimicrobial Resistance

Abstract

The most common type of microbial life in nature is found in bacterial biofilms, which are organized colonies attached to surfaces. They are thought to be the cause of up to 80% of human chronic illnesses and over two-thirds of microbiological infections. The global antimicrobial resistance (AMR) epidemic is intimately related to their clinical relevance; in 2021, bacterial AMR was linked to an estimated 4.71 million deaths worldwide. Unlike traditional genetic resistance, biofilm-associated resistance largely stems from the structural and chemical composition of biofilms. The extracellular polymeric substance (EPS) matrix, its three-dimensional organization, and the internal chemical heterogeneity are the main topics of this review, which summarizes the current knowledge on biofilm architecture. It investigates the mechanisms—diffusion limitation, metabolic heterogeneity, efflux pump activity, improved horizontal gene transfer, and quorum-sensing regulation—by which this architecture confers antimicrobial resistance and tolerance.. The clinical impact of biofilm-associated infections in medical devices, chronic wounds, and the airways of cystic fibrosis patients is discussed along with emerging therapeutic strategies targeting biofilms, including quorum-sensing inhibitors, matrix-degrading enzymes, nanotechnology-based delivery systems, and bacteriophage therapy. We conclude that effective management of infections associated with biofilms necessitates strategies that target multiple aspects of biofilm architecture, used in combination with, rather than as a replacement for, conventional antimicrobial therapy.