The Antibacterial Activity and Mechanism of Emilia Sonchifolia Against Methicillin Resistant Staphylococcus Epidermidis

Abstract Background: Bloodstream infections (BSIs) are a public health concern and cause substantial morbidity and mortality.The pathogen Staphylococcus epidermidis causes a significant number of BSIs. Antibiotics targeting Staphylococcus epidermidis have been the mainstay in BSIs. However, Conventional antibiotics have been eclipsed in combating with drug-resistant bacteria. Alternate ways of treating these antibiotic-resistant infections are thus urgently needed. Numerous studies have demonstrated that certain Chinese medicines exhibit notable antimicrobial activity and possess the ability to impede the development of bacterial resistance. Based on an extensive body of research in the field of traditional Chinese medicine(TCM), it has been determined that the Compositae plant exhibits a noteworthy anti-Methicillin-Resistant Staphylococcus Epidermidis (MRSE) effect. Methods: Initially, the Compositae plant Emilia sonchifolia underwent a screening process, followed by crushing and extraction using water. Subsequently, the extract was concentrated based on a specific ratio, dried, partitioned, and subsequently prepared for utilization.Therefore, the objective of this study was to examine the antibacterial efficacy and underlying antibacterial mechanism of Emilia sonchifolia against methicillin-resistant Staphylococcus epidermidis( MRSE). The antibacterial activity of Emilia sonchifolia against MRSE was assessed through in vitro tests measuring minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC). Furthermore, the antibacterial activity of Emilia sonchifolia against MRSE was evaluated in vivo using a mouse bloodstream infections model. Additionally, various aspects such as bacteria cell morphology and energy metabolism and defense mechanisms were investigated to explore the underlying antibacterial mechanisms of Emilia sonchifolia. Results: The results showed that MIC and MBC values of Emilia sonchifolia against MRSE were 5mg/mL and 20mg/mL, respectively. Meanwhile, Emilia sonchifolia can effectively treat MRSE induced bloodstream infections. Furthermore, the utilization of scanning electron microscopy and transmission electron microscopy techniques unveiled that the administration of Emilia sonchifolia induced alterations in the cellular structure of MRSE, leading to the disruption of both cell wall and membrane integrity. Additionally, exposure to Emilia sonchifolia resulted in a decrease in the enzymatic activities of succinate dehydrogenase, NADP-malate dehydrogenase, catalase, and superoxide dismutase. Conclusions: Thus, the aforementioned observations have contributed novel insights into the mechanistic understanding of Emilia sonchifolia's efficacy against MRSE, thereby offering potential strategies for managing MRSE infections.