Background: Multidrug resistance bacteria is rapidly spreading globally and has created an urgent need for alternative antimicrobial strategies to combat these bacteria. Green nanotechnology is an eco-friendly way of synthesizing Bioactive Nanoparticles with enhanced antimicrobial activities compared to conventional methods.
Objectives: The purpose of this study was to "green" synthesize magnesium oxide nanoparticles (MgO NPs) from an alcohol extract of Camellia sinensis (tea plant) and evaluate their antibacterial and anti-biofilm activity against clinical multidrug resistance bacterial isolates.
Methods: Magnesium Oxide nanoparticles were synthesized utilizing an alcohol extract of Camellia sinensis as a reducing/stabilizing agent. The synthesized MgO NPs were characterized by UV–Vis Spectroscopy, FTIR, XRD, SEM, AFM, EDX, AAS, and Zeta Potential analyses. The antibacterial activity of the MgO NPs was determined using minimum inhibitory concentration (MIC) determinations while their anti-biofilm activity was assessed by a microtiter plate crystal violet assay against clinical MDR Enterococcus faecalis and Klebsiella pneumoniae isolates. Data were expressed as mean ± SD.
Results: According to the study, MgO nanoparticles that were created by biosynthetic means had an average particle size range of 52-104 nm (SEM) and had evidence of nanoscale surface roughness from AFM. They also showed high colloidal stability with zeta potentials of -44.61 mV. MgO nanoparticles exhibited very strong (dose-dependent antibacterial effect on both E. faecalis and K. pneumoniae with a MIC value of 12.5 µg/ml, and significantly  reduced biofilm formation by 95.45-100% at sub-MIC concentrations.
Conclusion: Green-synthesized magnesium oxide (MgO) nanoparticles using extracts from Camellia sinensis, have very good anti-bacterial and anti-biofilm activities against multi-drug resistant (MDR) pathogens, and support the theorized use of green-synthesized MgO nanoparticles as an eco-friendly antimicrobial agent to reduce biofilm-related infections.