Antimicrobial and Antibiofilm Potency of Green Silver Nanoparticles Synthesized by Aqueous Garlic Extract Against Microbes Causing Otitis Media

Abstract

Aim of study: Otitis media (OM) is highly prevalent worldwide and is the main cause of hearing loss in developing countries. Resistant microorganisms and biofilm formation have become a major health and economic problem. The aim of this study was to establish an eco-friendly method for synthesis of silver nanoparticles using aqueous garlic extract and sunlight. Moreover, detect its potential to inhibit otitis media microbes.Methods: Basically, highly resistant and biofilm forming otitis media pathogenic isolates were determined by Kirby-Bauer disc diffusion method and their biofilm production qualitatively was tested. Then, compared their susceptibility to tetracyclin 30µg (for bacteria) and nystatin 100 µg (for fungi) alone and with different concentrations of green synthesized silver nanoparticles (AgNPs), as well as, their biofilm production. AgNPs were prepared by easy, fast, non-toxic, economically eco-friendly way, using the direct sunlight irradiation on aqueous garlic extract. Their characterization by UV- visible spectral analysis, TEM, DLS, XRD and FTIR were studied. Results: Two multidrug resistant bacterial isolates; Pseudomonas aeruginosa and Bacillus cereus were detected as biofilm producers with black colonies on congo-red agar and three resistant fungal isolates to nystatin; Penicillium chrysogenum, Aspergillus niger and Aspergillus flavus were tested against green synthesized AgNPs. Highly significant (p-value<0.001) antimicrobial and antibiofilm activity of biosynthesized AgNPs against tested pathogens were illustrated in this study. TEM images for Pseudomonas aeruginosa and Aspergillus flavus after treated with AgNPs, were exhibited shrinkage in the cytoplasmic materials, rupture of cell walls, precipitation of AgNPs particles inside the cells and biofilm was mostly disseminated.Conclusion: aqueous garlic extract that used to stabilize the AgNPs may be ideal natural candidates for future studies exploring their safely use in biomedical applications especially against the repeated infections caused by multi drug resistant (MDR) and biofilm forming microbials as in otitis media.