SarZ Is a Key Regulator of Biofilm Formation and Virulence in Staphylococcus epidermidis

Biofilm-associated infection by the leading nosocomial pathogen Staphylococcus epidermidis is a major problem for the public health system, but the regulation of this important phenotype is not completely understood. Using an especially discriminatory screen for genes influencing biofilm formation, we identified the transcriptional regulator SarZ as a novel important determinant of biofilm formation and biofilm-associated infection, based on a significant impact of sarZ on the transcription of the biosynthetic operon for biofilm exopolysaccharide. In addition, sarZ influenced the expression of a series of virulence genes, including lipases and proteases, resistance to an important human antimicrobial peptide, and hemolysis. Our study indicates a key role for the SarZ regulator in maintaining the typical S. epidermidis phenotype, which is characterized by pronounced biofilm formation and immune evasion, a likely reason for the success of S. epidermidis as a colonizer and pathogen in chronic, biofilm-associated infection.