The inhibitory effect of Anvillea garcinii methanolic extract on growth and biofilm formation of Staphylococcus aureus

BACKGROUND AND OBJECTIVESStaphylococcus aureus causes a wide range of diseases including skin infections, bacteremia, respiratory tract infections, and endocarditis. The pathogenicity of S. aureus is dependent on the combined effect of extracellular factors, toxins along with the ability of it to form biofilms. The aim of this study was to investigate the inhibitory effect of Anvillea garcinii methanolic extract (AGME), a native plant of Iran, on the growth and biofilm formation of S. aureus at the phenotypic and molecular levels.MATERIALS AND METHODSMicrodilution and Crystal Violet Staining Assay were used to evaluate the antibacterial and anti-biofilm activity of AGME against S. aureus ATCC۶۵۳۸ respectively. To assess the effect of methanolic extract on the expression of genes involved in biofilm formation, SarA, spa, and icaA, overnight culture of S. aureus was treated with the plant extract at ۴, ۱۶, and ۴۸ hours, followed by Real-time PCR to examine changes in gene expression.RESULTS AND DISCUSSIONAGME at concentrations ≥۱ mg/ml was able to inhibit ۱۰۰% of S. aureus growth and had bactericidal activity at a concentration of ۳ mg/ml. The highest percentage of inhibition of biofilm formation was observed at a concentration of ۰.۲۵ mg/ml methanolic extract. The expression of spa, Sar A, and ica A genes significantly decreased at concentrations of ۰.۵ mg/ml, ۰.۲۵ mg/ml, and ۰.۲۵ mg/ml, respectively.CONCLUSIONAGME has a significant inhibitory effect on the growth and biofilm formation of S. aureus. Further studies are necessary for the clinical application of this extract.