Synthesis of Silver Nanoparticles from Aeromonas caviae for Antibacterial Activity and In Vivo Effects in Rats

Silver nanoparticles (AgNPs) have excellent antimicrobial properties, as they can inhibit multidrug-resistant (MDR) pathogens. Furthermore, bio-AgNPs have potential applications in medicine due to their low toxicity and high stability. Here, AgNPs were synthesized from the biomass of Aeromonas caviae isolated from a sediment sample and subsequently characterized. The UV-Vis spectra of AgNPs in aqueous medium peaked at 417 nm, matching their plasmon absorption. The X-ray diffraction analysis (XRD) pattern of AgNPs showed four peaks at 2θ values, corresponding to Ag diffraction faces. Absorption band peaks at 3420.16, 1635.54, and 1399.43 cm^-1 were identified by Fourier-transform infrared spectroscopy (FTIR) analysis as belonging to functional groups of AgNP-associated biomolecules. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the nanoparticles are spherical and pseudospherical, with sizes of 15-25 nm. Agar well diffusion minimal inhibitory concentration (MIC) assays were used to assess the antibacterial activity of the nanoparticles against MDR pathogens. AgNPs exhibited antibacterial activity against MDR bacteria. Two groups of albino rats received intraperitoneal injections of AgNPs at 15 mg/kg or 30 mg/kg for 7 days. Blood, kidney, and liver samples were collected to investigate hematological, biochemical, and histopathological alterations. Administered AgNPs in rats fluctuated in liver and kidney function parameters. The ultrastructural impacts of AgNPs were more prominent at higher doses. The results proved the easy, fast, and efficient synthesis of AgNPs using A. caviae isolates and demonstrated the remarkable potential of these AgNPs as antibacterial agents. Nanotoxicological studies are required to identify the specific dose that balances optimal antibacterial activity with minimal toxicity to human health.