Influence of biosynthesized silver nanoparticles on keratinase activity and mycelial growth of dermatophytes

Objective Among different nanomaterials, silver nanoparticles (SNPs) exhibited high antifungal potency compared with other types of nanoparticles (NPs), and this property is often very helpful, particularly against fungi resistant to conventional antifungal agents. However, synthesis of SNPs can generate toxic waste during the preparation process. Accordingly, new technique using non-toxic routes have been researched for the synthesis of SNPs using cell-free filtrate of Aspergillus niger and evaluate their effect against some dermatophytes spp. Methods The proposal of our study was to biosynthesize SNPs using cell-free filtrate of Aspergillus niger as reducing agent. The characterization of biosynthesized SNPs was carried out by UV-Visible spectroscopy, Fourier transform infrared spectroscopic analysis (FTIR) and scanning electron microscopy (SEM). The antifungal effect of the NPs against dermatophytes was also evaluated. The minimum inhibitory concentration (MIC) was determined by broth microdilution method. Results Spherical NPs 15–50 nm in size were obtained. The biosynthesized SNPs exerted pronounced morphological alteration in the fungal mycelia. Additionally, the inhibition of keratinase activity of the tested dermatophytes was also recorded. Conclusion The results indicate that SNPs can be synthesized in ecofriendly, inexpensive and promising technique by fungal strain of A. niger, and it has considerable antifungal activity in comparison with other antifungal drugs

Study of the Inhibitory Effect of Thymus vulgaris and Eucalyptus camaldulensis on In vitro Growth of Listeria monocytogenes

    The antibacterial activity of the Thymus vulgaris and Eucalyptus camaldulensis was studied against Listeria monocytogenes . The inhibiting activity was evaluated by the agar well diffusion method. Results showed that the extracts of both tested plants demonstrated antimicrobial activity against the tested organism but the efficiency of the extracts was significantly affected by the solvent used in the extraction as well as plant species and the concentration. The aqueous extracts appeared to be the highly effective extracts against the tested organism ,it exhibited an inhibition zone 16 mm-24 mm for thyme and 15 mm-24 mm for eucalyptus in comparison with 21mm and23 mm for ampicillin and ciprofloxacin respectively .The alcoholic extract of thyme had no antibacterial activity in concentration of 25 and 50 mg /ml. The results of this study suggest that the antilisterial properties of these plants may be further investigated to explore the possibility of using them in the treatment of listerial infection