The Dual Role of the Medicinal Mushroom Fomitopsis pinicola in Inhibiting Biofilm and Reducing Antibiotic Resistance of Methicillin‐Resistant Staphylococcus aureus

İngilizce (OpenAlex)

ABSTRACT This study investigates the antimicrobial, antibiofilm, and anti‐quorum sensing activity of Fomitopsis pinicola against methicillin‐resistant Staphylococcus aureus (MRSA) strains and its potential to improve the efficacy of conventional antibiotics and exert selective cytotoxic effects on cancer cells. Ethanolic extracts of F. pinicola were analyzed for antibacterial activity by MIC and time‐kill assays. Synergistic interactions with antibiotics were quantified using checkerboard assays. Antibiofilm activity was analyzed on polystyrene and stainless‐steel surfaces. Anti‐quorum sensing activity was determined by the inhibition of violacein in Chromobacterium violaceum . Efflux pump inhibition was assessed by the accumulation of the ethidium bromide. The down‐regulation of virulence genes ( agrA , hla ) was measured by qRT‐PCR (quantitative real‐time reverse‐transcription PCR). FT‐IR (Fourier transform infrared spectroscopy) spectroscopy characterized the bioactive compounds, and the cytotoxicity assays on HT‐29 colon cancer and Vero cells evaluated selective toxicity. The extract showed strong antibacterial effects with a MIC of 312.5 μg/mL and concentration‐dependent bactericidal activity. Synergistic interactions with antibiotics led to FIC indices ≤ 0.5. The extract significantly inhibited biofilm formation and eradicated already formed biofilms. Sub‐MIC concentrations reduced quorum sensing by 85.01%, inhibited efflux pump activity, and down‐regulated virulence‐associated genes. FT‐IR analysis confirmed the presence of triterpenoids and terpenoids. The extract displayed selective cytotoxicity on HT‐29 cancer cells, showing strong inhibition, while normal Vero cells were spared. These results emphasize the potential of F. pinicola as a robust candidate for antimicrobial therapeutics, especially against biofilm‐associated and multidrug‐resistant pathogens, as well as a selective anticancer agent.