Quorum sensing systems of Staphylococcus aureus
Staphylococcus aureus is a major human pathogen and a leading cause of nosocomial infections. Its ability to cause a variety of different diseases and to survive under harsh conditions has been attributed to its vast reservoir of virulence determinants and regulatory systems allowing the pathogen to rapidly respond to changing conditions and to fine-tune the production of its offensive and defensive virulence factor arsenal in response to host cell signals. One of these global regulators of virulence determinant production in S. aureus is RNAIII, the effector molecule of the “accessory gene regulator” (agr) locus. The agr locus encodes the major quorum sensing (QS) system of this species that controls the expression of its target genes by a classical two-component signalling module. Unlike other QS systems in G+ bacteria, the agr system of S. aureus has evolved into different subgroups, allowing it to identify its own group and to discriminate between and interfere with signalling of other groups and species.
Like other staphylococcal species, S. aureus harbours an ortholog for a second signalling system, luxS, which is involved in the production of the common autocrine signalling molecule AI-2. However, unlike its close relative, Staphylococcus epidermidis, S. aureus neither seems to produce nor to respond to this universal signalling molecule.
Saarland University, Campus B2.1, 02
Markus Bischoff, Institut für Medizinische Mikrobiologie und Hygiene, UdS
HIPS-DDOP, Rolf Hartmann