Staphylococcus aureus accessory gene regulator (agr) system (agr system)

The Staphylococcus aureus quorum-sensing system, specifically the accessory gene regulator (agr) system, is a density-dependent signaling mechanism that coordinates the expression of virulence factors. It operates via a two-component system consisting of the transmembrane sensor kinase AgrC and the response regulator AgrA, which are activated by an autoinducing peptide (AIP) (Wang, B., & Muir, T. W. (2016). Cell Chemical Biology). At high cell densities, the system triggers the production of various toxins, such as alpha-hemolysin and phenol-soluble modulins, while downregulating surface adhesion proteins to facilitate bacterial dispersal and tissue invasion (Tan, L., et al. (2018). Frontiers in Microbiology). Because the agr system is central to the pathogenesis of S. aureus, including antibiotic-resistant strains like MRSA, it is a major target for anti-virulence therapies. Drugs targeting this system aim to disarm the pathogen without killing it, potentially reducing the selective pressure for antibiotic resistance (Sully, E. K., et al. (2014). PLoS Pathogens).

Other names

Staphylococcus aureus quorum-sensing systemagr locusAIP-mediated signaling systemAccessory gene regulator system

Inhibition of the AgrC histidine kinase receptor or the AgrA response regulator to suppress the transcription of virulence-related genes and the effector molecule RNAIII (Nielsen, A., et al. (2014). Marine Drugs).