Phenotype and expression profile analysis of Staphylococcus aureus biofilms and planktonic cells in response to Licochalcone A. Staphylococcus aureus

Staphylococcus aureus (S. aureus) is one of the most important pathogens in humans and animals. The formation of S. aureus biofilm is considered an important mechanism of antimicrobial resistance. Therefore, finding effective drugs against the biofilm produced by S. aureus has been a high priority. Licochalcone A, a natural plant product, was reported to have antibacterial activities and showed good activity against all 21 tested strains of S. aureus biofilm and planktonic cells. To detect the possible molecular mechanism of Licochalcone A against S. aureus biofillm or planktonic cells, Affymetrix GeneChips were used to determine the global comparative transcription of S. aureus biofilm and planktonic cells triggered by treatment with sub-bactericidal and sub-inhibitory concentrations of Licochalcone A, respectively. Overall design: Staphylococcus aureus planktonic cells and biofilm were exposed for 60 minutes to Licochalcone A at concentration of 2 μg/ml (1/2× MIC) and 64 μg/ml (4× MIBC), respectively. 4 samples including 4 control samples are analyzed.