Bacterial quorum sensing: a new target for anti-infective immunotherapy

Background: Cell-to-cell communication via exchange of small molecules, ‘autoinducers’, is a widespread phenomenon among Gram-negative and -positive bacteria. This intercellular signaling that synchronizes population-wide gene expression in a cell-density-dependent manner is termed ‘quorum sensing’ (QS). The discovery that Gram-negative bacteria employ non-peptide structures, N-acyl homoserine lactones, to globally regulate production of secondary metabolites and proteins, initiated a new area of research. Subsequently, other quorum-sensing systems and small signaling molecules were identified. With the emergence of antibiotic-resistant bacteria, most prominently methicillin-resistant Staphylococcus aureus(MRSA) and Pseudomonas aeruginosa, new approaches for combating infections are needed. Inhibition of QS results in attenuation of virulence rather than direct killing of microbes. Objective: We highlight current trends in preventing bacterial infections using quorum-quenching strategies. Methods: We mainly focus on P. aeruginosaand S. aureusand their QS systems as targets for intervention. Results/conclusion: New research strongly suggests that QS systems represent attractive targets for discovery of novel anti-infective agents, including immunotherapeutic strategies.