Staphylococcus aureus gene expression in a rat model of infective endocarditis

S. aureus has a propensity to cause endocarditis; diabetes mellitus is a frequent underlying comorbitity in patents with S. aureus endocarditis. S. aureus Affymetrix GeneChips were used to compare S. aureus expression properties in cardiac vegatations isolated from diabetic and nondiabetic rats. S. aureus Affymetrix GeneChips were also used to compare the S. aureus expression properties of cardiac vegatations (both diabetic and nondiabetic) in comparsions to planktonic cells. Few differences were observed between the expression properties of S. aureus harvested from diabetic vs. nondiabetic cardiac vegatations. Significant differences were observed between the expression properties of S. aureus harvested from cardiac vegetations in comparison to exponential and/or stationary phase planktonically grown cells. S. aureus strain COL was used to establish cardiac vegetations in diabetic and nondiabetic rats or grown in laboratory medium to exponential or stationary phase, total bacterial RNA was isolated, labeled and applied to Affymetrix GeneChips. We sought to determine whether the transcriptional profiles of S. aureus differed in diabetic vs. nondiabetic rats and whether vegetations differed from that of planktonic S. aureus.