Fabrication And Optimization of Bio-silver Nanoparticles: Activity Evaluation Against Beta-lactamases-Resistant Enterococcus Faecalis

Abstract Due to the presence of antibiotic-resistant genes, treatment options of clinical isolates are exceedingly limited. This study was aimed to fabricate, optimize, characterize, and evaluate the action of silver nanoparticles (AgNPs) against a clinical isolate of Enterococcus faecalis. A combination of cell-free supernatant (C-FS) of the filamentous fungus Fusarium solani and Gram-negative Comamonas aquatica for AgNPs formation was proposed; the antigrowth and antibiofilm of AgNPs against E. faecalis harboring blaTEM and blaCTX-M genes were assessed. The ratio of 1:2 v/v (C-FS:AgNO3) at pH 9.0 for 72 h in 1 mM AgNO3 were the optimal conditions for AgNPs formation. UV-vis absorption peak appeared at 425 nm and the crystalline nature of synthesized particles was verified by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the interaction of protein molecules with the AgNPs. Transmission electron microscopy (TEM) analysis demonstrated that fabricated AgNPs were relatively monodispersed, approximately spherical, and of size 2-7.5 nm. blaTEM and blaCTX-M were detected in E. faecalis; the growth and biofilm of E. faecalis were significantly decreased by the action of 12.5 µg/mL AgNPs. This is the first study proposing alternative sources to form AgNPs via synergistic metabolites of F. solani and C. aquatica. The results here offer a foundation for developing an effective therapy using AgNPs against clinical pathogens.