Global transcriptome analysis of Staphylococcus aureus biofilms in response to innate immune cells

S. aureus biofilms are associated with the organism's ability to cause disease. Biofilm associated bacteria must cope with the host's innate immune system. We used commercially available Affymetrix S. aureus GeneChips to compare the gene expression properties of 4 and 6 day established biofilms following short (1 hr)- and long (24 hr)- term exposure to macrophages and neutrophils. S. aureus strain USA300 LAC biofilms where formed for 4 or 6 days. Established biofilms were then exposed to macrophages for 1 or 24 hr. Alternatively, biofilms were exposed to neutrophils for 1 or 4 hr. Total bacterial RNA was isolated and subjected to GeneChip hybridization and analysis. We sought to determine the regulatory effects of Macrophages and Neutrophils on established S. aureus biofilms.