One-Pot and Environmentally Friendly Biosynthesis of Silver Nanoparticles from Enterococcus durans: Activity Against Fluconazole-Resistant Pathogenic Candida tropicalis

Metallic nanoparticles with antimicrobial properties have obtained the status of a new generation of antifungal drugs. This study described a method for the synthesis of biogenic silver nanoparticles (Bio-AgNPs) using cell-free supernatant containing enterocin from Enterococcus durans and assessed the antifungal potential against fluconazole-resistant Candida tropicalis. Bio-AgNPs was confirmed visually by the appearance of a reddish-brown color formation. A sharp absorbance peak at 448 nm was found using a UV-visible spectrophotometer, confirming the presence of Bio-AgNPs. Fourier transform infrared spectroscopy, differential light scattering, energy dispersive spectroscopy, and transmission electronic microscopy analyses were employed to characterize the Bio-AgNP. Reduction of Ag+ ions in solution with CFS from E. durans produced spherical Bio-AgNPs with an average size of 169.11 nm and zeta potential of − 25.3 mV. The anti-Candida activity of Bio-AgNPs and its synergism with fluconazole were determined using agar well diffusion and broth microdilution method. Bio-AgNPs at a concentration of 32.17 μg/mL promoted zones of inhibition that ranged from 18.5 ± 0.7 to 23 ± 1.7 mm among C. tropicalis strains. The minimum inhibitory concentration of Bio-AgNPs that inhibit 80