Plant extracts typically require higher concentrations to demonstrate positive inhibition against bacteria, and even higher concentrations may be necessary for resistant bacteria. This lack of inhibition can be attributed to the specific nature of these bacterial strains, requiring a higher concentration of the synthesized copper nanoparticles for effective inhibition. Similar findings were reported by Dashtizadeh et al. , where CuNPs showed no zone of inhibition (ZOI) against various bacteria and yeast strains.