Quorum Sensing and Biofilm Dynamics in Pathogenic Bacteria

Quorum sensing is a population-density-dependent signalling mechanism by which bacteria coordinate gene expression through the secretion and detection of small diffusible molecules. In pathogenic species, this regulatory network governs the production of virulence factors, motility apparatus and the extracellular polymeric substances that constitute biofilm matrices. Biofilms are structured microbial communities attached to surfaces and encased within a self-produced matrix of polysaccharides, proteins and extracellular DNA. They undergo a developmental cycle of initial attachment, microcolony formation, maturation and dispersion. Within biofilms, bacteria enjoy enhanced tolerance to antibiotics and host immune defences, leading to persistent infections on medical devices, in chronic wounds and in respiratory tracts. The interplay between quorum sensing and biofilm dynamics is central to infection resilience and environmental survival. Disrupting these intercellular communications or targeting biofilm architecture has become a global priority in the search for novel antimicrobial strategies and anti-virulence therapies.

Research from Nature Portfolio

Recent studies have revealed that secreted redox-active metabolites known as phenazines bind directly to extracellular DNA within Pseudomonas aeruginosa biofilms. This intercalation alters the physical properties of the matrix, enhancing electron transfer and viscosity, and thereby stabilising biofilm architecture. Loss of phenazine production or degradation of extracellular DNA results in disordered and less robust biofilms, pointing to phenazine–DNA complexes as promising targets for anti-biofilm intervention.

Investigations into plant-derived small molecules have shown that vanillic acid, isolated from fruit extracts, interferes with quorum sensing in Serratia marcescens. This compound diminishes the synthesis of acyl homoserine lactones, suppresses biofilm formation and downregulates proteins involved in surface layer and flagellin assembly. In a Caenorhabditis elegans infection model, vanillic acid treatment increased host survival, underscoring the therapeutic potential of natural quorum sensing inhibitors.

Quorum Sensing and Biofilm Dynamics in Pathogenic Bacteria publication trend

The graph below shows the total number of articles in quorum sensing and biofilm dynamics in pathogenic bacteria across all publications each year (not limited to Nature Index journals).

Technical terms

Quorum sensing: A bacterial communication system using secreted signal molecules to coordinate collective behaviours once a threshold concentration is reached.

Biofilm: A structured community of microorganisms adhering to a surface and enclosed in a self-produced matrix of extracellular polymeric substances.

Extracellular polymeric substances (EPS): A complex mixture of polysaccharides, proteins, lipids and extracellular DNA that form the protective matrix of a biofilm.

Acyl homoserine lactones (AHLs): A class of small diffusible signalling molecules used predominantly by Gram-negative bacteria to mediate quorum sensing.

Phenazine: A family of redox-active secondary metabolites produced by certain bacteria that contribute to biofilm stability and pathogenicity.

References

1. Phenazine virulence factor binding to extracellular DNA is important for Pseudomonas aeruginosa biofilm formation. Scientific Reports (2015).
2. Vanillic acid from Actinidia deliciosa impedes virulence in Serratia marcescens by affecting S-layer, flagellin and fatty acid biosynthesis proteins. Scientific Reports (2017).
3. Synergistic effect of propyl gallate and antibiotics against biofilms of Serratia marcescens and Erwinia carotovora in vitro. LWT (2023).
4. Ascorbic acid modulates the structure of the Pseudomonas aeruginosa virulence factor pyocyanin and ascorbic acid-furanone-30 combination facilitate biofilm disruption. Frontiers in Microbiology (2023).
5. The antivirulence activity, transcriptomics of EGCG and its protective effects on zebrafish infected by Aeromonas hydrophila. Frontiers in Cellular and Infection Microbiology (2023).