Impact of staphylococcus aureus accessory gene regulator system on virulence and antibiotic resistance

Accessory gene regulator(agr)-mediated quorum sensing system plays a crucial role in staphylococcal aureus(S.aureus) pathogenesis.It upregulates secreted virulence factors and downregulates cell surface proteins, thereby influencing invasiveness of S. aureus and cell dispersal from biofilms.S.aureus can be divided into four groups according to the polymorphism in the sequence of agr system and of its corresponding receptor.Auto-inducing peptide(AIP)can activate the agr locus in the same group, but mutually inhibit agr locus from different groups.Recent researches have demonstrated that agr dysfunction is common among S. aureus isolates.Certain agr classes and agr-defective strains have been associated with specific clonal complexes and a variety of diseases, influencing the courses of infections and the antibiotic resistance.In this paper, the effects of different agr types and dysfunctional agr on the virulence, antibiotic resistance and biofilm formation of S. aureus were reviewed. Key words: Staphylococcus aureus; Accessory gene regulator system; Virulence; Antibiotic resistance