Editor: Jan-Ingmar Flock
Subinhibitory concentrations of β-lactam induce haemolytic activity in Staphylococcus aureus through the SaeRS two-component system
Article first published online: 19 DEC 2006
FEMS Microbiology Letters
Volume 268, Issue 1, pages 98–105, March 2007
How to Cite
Kuroda, H., Kuroda, M., Cui, L. and Hiramatsu, K. (2007), Subinhibitory concentrations of β-lactam induce haemolytic activity in Staphylococcus aureus through the SaeRS two-component system. FEMS Microbiology Letters, 268: 98–105. doi: 10.1111/j.1574-6968.2006.00568.x
- Issue published online: 15 JAN 2007
- Article first published online: 19 DEC 2006
- Received 23 October 2006; revised 13 November 2006; accepted 13 November 2006.First published online 18 December 2006.
- fibrinogen-binding protein
SaeRS is a two-component system that has been characterized as a positive regulatory system for the expression of several virulence factors, including coagulase, α-, β- and γ-haemolysins, nuclease, and fibronectin-binding proteins in Staphylococcus aureus. Previously, the SaeRS system was found to be induced at the transcriptional level by β-lactam. Here, we found that subinhibitory concentrations of β-lactam induce haemolytic activity in the S. aureus N315 strain but not in the saeRS null mutant KSA. Comparison of the transcriptional profile of the N315 and KSA strains by microarray analysis reveals that the SaeRS system modulates the regulation of coagulase (coa), α-, β- and γ-haemolysins (hla, hlb and hlg), nuclease (SA0746), fibrinogen-binding proteins (emp, efb, SA1000 and SA1004), fibronectin-binding protein B (fnbB), and 13 other genes. Further, the use of cefoxitin as a signal inducer reveals that the SaeRS system appears to modulate 22 additional genes as a secondary regulon, including the staphylococcal accessory regulators SarA and SarT and the Clp protease ATPase subunits ClpB and ClpL. These observations suggest that β-lactam is able to induce the SaeRS system, which acts as a crucial signal transduction system for S. aureus pathogenicity rather than antimicrobial resistance.