Multi-resistant bacteria isolated in clinical centers currently constitute one of the most serious health problems worldwide. Multiple therapeutic alternatives are investigated, especially the use of nanomaterials. Metallic nanoparticles have been investigated for many years. One of the most relevant properties is their antibacterial capacity. However, few studies associate this property with bacteria isolated from clinical infections. In this study, the antimicrobial activity of AgNPs and CeO2NPs against clinically important bacteria such as S. aureus, P. aeruginosa, and A. baumannii, from clinical origin, was evaluated. The synthesis of nanoparticles is presented through a green synthesis method with the use of tannic acid as a reducing agent. The characterization of the nanoparticles was carried out using UV-Vis spectrum, Transmission Electron Microscopy, Dynamic Light Scattering and X-ray diffraction. The antibacterial effect against strains of clinical origin was evaluated using the agar diffusion technique, where a wide range of spectrum of activity for AgNPs. This study shows the importance of generating biological assays obtaining strains of clinical origin due to their great diversity and complexity in relation to the use of known bacterial strains, particularly if the new therapies under study are synthesized as an alternative to the
antimicrobials currently used.