Resumo

ZAVALETA ESPEJO, Gina et al. Antibacterial effect of ZnO nanoparticles on Staphylococcus aureus and Salmonella typhi. Arnaldoa [online]. 2019, vol.26, n.1, pp.421-430. ISSN 1815-8242.  http://dx.doi.org/10.22497/arnaldoa.261.26122.

The antibacterial effect of ZnO nanoparticles, obtained by the modified sol-gel method, on Staphylococcus aureus ATCC 25923 and Salmonella typhi was evaluated, using the modified KirbyBauer method with 7 mm diameter holes made with sterile punches instead of discs. A completely randomized block experimental design was developed with four treatments and a negative control (PEG 6000) with five repetitions. The concentrations of ZnO nanoparticles (0.4, 0.8, 1.2, 1.6, 2.0 mg/ ml) were prepared in aqueous solutions of PEG 6000 at the concentration of 100 mg/ml. The results obtained show a relationship between the increase in the concentration of the nanoparticles and the antibacterial effect, noticing the highest growth inhibition halo (14.78 mm) of S. aureus at the concentration of 2.0 mg/ml, unlike S. typhi, which had a smaller diameter of inhibition (11.01 mm) at the same concentration. This is probably because the nanoparticles generate free radicals (ROS), which when interacting with the bacterial cell wall cause an extrusion of the intracellular content due to the oxidative damage of proteins and lipids, generating in this way an antibacterial effect. Due to this, it is presumed that in the future they could become an alternative to fight bacterial diseases.

Palavras-chave : antibacterial; growth; Kirby-Bauer; nanoparticles; ZnO.

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