Matrix-controlled emergence of biofilm architecture shapes antimicrobial survival

Biofilms are intricate microbial communities that produce an extracellular matrix, which is believed to provide them with protection against antimicrobial agents. However, the connection between individual bacterial biofilm production and collective architecture, as well as antimicrobial resistance, is not fully understood. Researchers studied the impact of the csgD master biofilm regulator on Salmonella enterica biofilms, discovering that increasing matrix production alters biofilms from dense, uniform packings to sparse, aligned communities by modifying cell-cell interactions.

Using biofilm measurements alongside reaction-diffusion modeling, they demonstrated that these structural changes result in various antimicrobial killing patterns. Killing is more dominant near the liquid-biofilm interface and becomes more uniform throughout the community. Consequently, increasing matrix production unexpectedly diminishes antimicrobial survival by transitioning the biofilm into different transport regimes. Additionally, strain-specific physiological differences further influence antimicrobial depletion.

These findings suggest that extracellular polymeric substances (EPS), rather than being mere barriers, actively shape antimicrobial susceptibility by reorganizing biofilm architecture and its transport properties. EPS thus creates a physical link between molecular regulation, collective architecture, and antimicrobial survival, offering a quantifiable framework to understand how bacterial matrix production generates emergent biofilm functions.