Abstract:[Background] Methicillin-resistant Staphylococcus aureus (MRSA) is a common opportunistic pathogen in hospitals and the community, characterized by multi-drug resistance, high morbidity and mortality, and MRSA infection has become one of the common problems in the global medical community. [Objective] To study the antibacterial mechanism of rhubarb acid against MRSA. [Methods] To determine the minimum inhibitory concentration (MIC) of rhubarb acid on MRSA by two-fold dilution method; to determine the dynamic inhibitory effect of rhubarb acid on MRSA by MIC; to establish a biofilm model and determine the effect of rhubarb acid on viable bacteria in biofilm barrier, and to observe the effect of rhubarb acid by scanning electron microscope. The morphological changes of MRSA bacteria after the action of different concentrations of rhubarb acid; the effects of rhubarb acid on the depolarization and permeability of MRSA cell plasma membrane were determined by immunofluorescence staining and fluorescence analysis. [Results] The MIC of rhein on MRSA was 8 μg/mL; rhein had obvious inhibitory effect on the surviving bacteria in the biofilm, and under the effect of rhein, the morphology of the bacterial body was obviously wrinkled and damaged, and the severity of damage was positively correlated with the concentration; with the increase of rhein concentration and effect time, the fluorescence intensity changed obviously, and the permeability of the cell membrane changed. [Conclusion] Rhein mainly damaged the cell membrane of bacteria, thus inhibiting the growth and reproduction of bacteria.
