Green Nanoarchitectonics of Silver Nanoparticles for Antimicrobial Activity Against Resistant Pathogens

Antimicrobial resistance represents a serious concern to public health, being responsible for hospital infections, affecting mainly immunosuppressed patients. Thus, nanotechnology appears as an alternative to solve this problem, through the application of metallic nanoparticles with antimicrobial activity. The present work aims to synthesize and characterize AgNPs from Klebsiella pneumoniae (AgNPs-KP) and Aloe vera extract (AgNPs-AV), evaluating the antimicrobial activity against Klebsiella pneumoniae carbapenemase (KpC) and the cytotoxicity in the L929 cell line. AgNPs were prepared by the biosynthetic method using Klebsiella pneumoniae and were characterized by XRD, FTIR and SEM-EDS. Antimicrobial activity was tested using the MIC and MBC. The cytotoxicity was evaluated by the MTT method and neutral red. The production of ROS and nitrogen RNS tests were performed in the L929 cell line. Thus, it was possible to confirm the production of AgNPs-KP, through morphological, structural and elemental analysis. AgNPs from Klebsiella pneumoniae had potent antimicrobial activity in low concentration against antimicrobial resistant pathogens with MIC 9.76 µg mL^-1 and MBC 9.06 µg mL^-1. Moreover, AgNPs-KP in concentrations of 10, 30 and 100 µg mL^-1 did not show cytotoxic properties for the L929 fibroblast, where only the cytotoxic effect was observed in high concentrations (300 µg mL^-1). AgNPs-KP did not produce ROS about the analyzed concentrations and RNS production was only in the highest concentration of 3000 µg mL^-1. Therefore, AgNPs biosynthesized by Klebsiella pneumoniae have potential medical applicability as a promising antimicrobial agent, using a simple and low-cost method, correlating nanomedicine as nanostructured materials.