Inhibitory activity and mechanism of resveratrol against methicillin-resistant Staphylococcus aureus in beef: A...

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a significant pathogen in animal-derived food production. The use of natural antimicrobial agents is becoming a promising method to reduce the risk of MRSA. Resveratrol, a natural product, may be used as an alternative green preservative for the meat industry. This study investigated the antimicrobial efficacy of resveratrol against MRSA, including its inhibitory activity on MRSA inoculated in beef under different storage conditions (4 °C for 7 days and 25 °C for 3 days). The antimicrobial mechanism was further investigated via assessments of MRSA alkaline phosphatase (AKP) activity, cell leakage, propidium iodide staining, scanning electron microscope observations, intracellular reactive oxygen species (ROS) levels, and proteomic profiles. The results demonstrated that the minimum inhibitory concentration (MIC) of resveratrol on MRSA was 200 μg/mL. Resveratrol significantly inhibited the MRSA growth in beef, in which the MIC group reduced 1.55 and 2.56 log CFU/g MRSA compared to the control group without resveratrol after 7-day storage at 4 °C and 3-day storage at 25 °C, respectively. This was mainly attributed to the disruption of the cell membrane and wall structure rather than the ROS-mediated oxidative damage. Proteomic analysis revealed that resveratrol at sub-MIC (100 μg/mL) led to interference in cell wall and membrane synthesis, causing damage to MRSA cells. Additionally, some key enzymes were upregulated in response to resveratrol stress, including glucose-6-phosphate dehydrogenase in the pentose phosphate pathway, as well as ornithine aminotransferase and pyrroline-5-carboxylate reductase in the arginine and proline metabolism pathways. Furthermore, the resveratrol treatment reduced toxin production and the invasion ability of MRSA. These results indicated that resveratrol demonstrated significant application value in controlling foodborne MRSA within the beef industry and can provide important technical support for the safety control and quality assurance of beef products.