Antibacterial Activity of Silver Nanoparticles and Their Combination with Zataria multiflora Essential Oil and Methanol Extract

BACKGROUND Against a variety of antimicrobial resistant pathogens, the scientists attempted substitution of antimicrobial medicine with various nanoparticles and plant-based antibacterial substances. OBJECTIVES The aim of this study was to assess the antibacterial effects of silver nanoparticles solely and in combination with Zataria multiflora essential oil and methanolic extract on some photogenic bacteria. METHODS Minimum inhibitory concentrations (MICs) and fractional inhibitory concentrations (FICs) of plant essential oil, methanolic extract, and silver nanoparticles against bacteria were evaluated using the broth microdilution method and check board microtiter assays. RESULTS The results of the experiment showed that the MIC and minimal bacterial concentration (MBC) values of Ag-NPs against all strains were in the range of 15.625 - 500 µg/mL, and values for the essential oil and plant extract were in the range of 1.56 - 100 mg/mL. CONCLUSIONS Silver nanoparticles were observed to have additive effects with essential oil against Staphylococcus epidermidis and S. aureus. The obtained results suggest the need for further investigations of the antibacterial effects of the combination of silver nanoparticles with other plant extracts and essential oils.