Artemisia princepsInhibits Biofilm Formation and Virulence-Factor Expression of Antibiotic-Resistant Bacteria

Abstract

In this study, we used ethanol extract ofA. princepsand investigated its antibacterial effects against MRSA. Ethanol extract ofA. princepssignificantly inhibited MRSA growth and organic acid production during glucose metabolism at concentrations greater than 1 mg/mL (P < 0.05). MRSA biofilm formation was observed using scanning electron microscopy (SEM) and safranin staining.A. princepsextract was found to inhibit MRSA biofilm formation at concentrations higher than 2 mg/mL significantly (P < 0.05). Bactericidal effects of theA. princepswere observed using confocal laser microscopy, which showed thatA. princepswas bactericidal in a dose-dependent manner. Using real-time PCR, expression ofmecA, an antibiotic-resistance gene of MRSA, was observed, along with that ofsea, agrA, andsarA.A. princepssignificantly inhibitedmecA, sea, agrA, andsarA, mRNA expression at the concentrations greater than 1 mg/mL (P < 0.05). The phytochemical analysis ofA. princepsshowed a relatively high content of organic acids and glycosides. The results of this study suggest that the ethanol extract ofA. princepsmay inhibit proliferation, acid production, biofilm formation, and virulence gene expressions of MRSA, which may be related to organic acids and glycosides, the major components in the extract.