Antibacterial, Antibiofilm, and Quorum Quenching Properties of Biogenic Chitosan Silver Nanoparticles Against Staphylococcus aureus

Chitosan-Silver Nanoparticles are effective at targeting various molecular and physiological activities of bacteria. The current study focused on the phytosynthesis of chitosan-silver nanoparticles (CS-AgNPs) from Acacia glauca leaf extract and assessed their impact on the expression of quorum sensing and hemolysin genes in Staphylococcus aureus. The appearance of a dark brown color and a surface plasmon resonance peak at 432 nm were the primary indicators of CS-AgNP formation. SEM and TEM images revealed that the nanoparticles had an almost spherical shape with an average particle size of 8 nm. A zeta potential of + 33 mV confirmed high colloidal stability, and the XRD pattern matched the silver crystal lattice structure, indicating a high degree of crystallinity. The synthesized nanoparticles exhibited a strong anti-Staphylococcus aureus effect with a minimum inhibitory concentration (MIC) of 4 µg/mL. Moreover, the CS-AgNPs exhibited significant antibiofilm activity. RT–PCR analysis revealed a significant reduction in the translation of quorum sensing and hemolysin genes upon exposure to a subinhibitory concentration of CS-AgNPs. Chitosan-silver nanoparticles have the potential to be effective antibacterial agents by targeting the molecular mechanisms of multidrug-resistant S. aureus.