Efficacy of pristimerin against Staphylococcus aureus planktonic cultures and biofilms

Abstract

This study aimed to evaluate the antimicrobial and antibiofilm activity of pristimerin, a phenolic triterpenoid extracted from various plants, against Staphylococcus aureus strains. The microtitre broth dilution method and disk diffusion assay were used to determine the minimum inhibitory concentrations (MICs) and the antimicrobial activities of pristimerin against both methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). The MIC values for each strain treated with pristimerin (0.05 μM against MRSA and 0.0005 μM against MSSA) were significantly lower than those of strains treated with ampicillin (0.5 μM against MRSA and 0.05 μM against MSSA). The antimicrobial mechanism of pristimerin against S. aureus was elucidated through the outer membrane permeabilization assay. The confocal scanning laser microscopy (CLSM) revealed that pristimerin could disrupt the S. aureus biofilm structure. Furthermore, pristimerin showed potent activity against S. aureus growth inhibition and biofilm dispersal in various fresh produces (lettuce, perilla leaves, and kale leaves). These results demonstrate that pristimerin has significant value as a natural compound providing antimicrobial and antibiofilm effects and can be used in food preservatives.