Evaluation of the Inhibitory Effect of Copper Oxide Nanoparticles Biosynthesized by Streptococcus salivarius against Staphylococcus aureus and Pseudomonas aeruginosa

Abstract

  The copper oxide nanoparticles (CuO NPs) gained prominence because of their unique physical and chemical characteristics and applications as an antimicrobial. Production of nanoparticles through biological processes using microorganisms is an environmentally friendly technique for synthesizing nanoparticles. In the current study, the inhibitory effect of CuO NPs produced using the microorganism Streptococcus salivarius on Staphylococcus aureus and Pseudomonas aeruginosa was assessed. Copper oxide nanoparticles were produced through bacterial filtrate and copper sulfate as precursor. The nanoparticles produced were analyzed using FTIR, XRD, SEM, TEM, and EDX. TEM analysis revealed nanoparticles of size 40-110 nm, whereas SEM revealed the existence of particles ranging from 30-75 nm. EDX analysis confirmed copper and oxygen as the most prevalent detected elements, constituting 80.43% and 19.57%, respectively. The antimicrobial potential was assessed at various concentrations of 1000, 500, 250, 125, and 62.5 µg/mL using agar well-diffusion technique. The maximum inhibition zone was noticed at a concentration of 1000 µg/mL, with 16.67 ± 0.58 mm inhibition zone against S. aureus and 17.67 ± 0.58 mm against P. aeruginosa. Inhibition zones of 14.33 ± 0.58 mm and 16.33 ± 1.15 mm were noted for S. aureus and P. aeruginosa, respectively, at a concentration of 500 µg/mL. At a concentration of 250 µg/mL, inhibition zones of 7.33 ± 0.58 mm and 14.33 ± 1.53 mm were recorded against S. aureus and P. aeruginosa, respectively. Inhibition zones of 0.00 ± 0.00 mm and 9.67 ± 0.58 mm were noted against S. aureus and P. aeruginosa, respectively, at a concentration of 125 µg/mL whereas inhibition zones of 0.00 ± 0.00 mm and 7.33 ± 0.58 mm were noted, respectively, at a concentration of 62.5 µg/mL. Therefore, it is evident.