Rhodethrin and Antibiotic Synergism to Combat <scp> <i>Enterococcus faecalis</i> </scp> and Inhibit Biosynthesis of Extracellular Polymeric Substances

Biofilms are structured communities of microorganisms embedded in extracellular polymeric substances (EPSs) that adhere to surfaces or interfaces. These biofilms are resistant to antimicrobial agents and are responsible for persistent infections. An effective strategy is needed to inhibit the biogenesis of polymeric substances by Enterococcus faecalis. This study explored a synergistic approach using an indole terpenoid molecule, rhodethrin, combined with chloramphenicol to disrupt EPS production by E. faecalis. TGA revealed three stages of decomposition: moisture content (15% at 35°C-200°C), pyrolysis temperature (40%-60% at 200°C-400°C), and polysaccharide crystals (< 10% at < 600°C). X-ray diffraction analysis indicated that the EPS consisted of 40%-60% crystalline and 60%-75% amorphous domains. FTIR analysis also identified various functional groups, like aliphatic CH₂, hydroxyl groups, aliphatic methyl groups, asymmetrical C=H stretching, and amine groups. LCMS analysis provided insights into the molecular mass of EPS constituents. SEM analysis revealed a condensed matrix characterized by polymeric carbohydrates and filamentous structures. The results showed a significant therapeutic importance of their combined effects on the biosynthesis of EPSs in E. faecalis. Further research on their molecular mechanisms and clinical applications is essential to harness their benefits and develop effective treatment against biofilm-associated infections caused by E. faecalis.