Pseudomonas indica-Mediated Silver Nanoparticles: Antifungal and Antioxidant Biogenic Tool for Suppressing Mucormycosis Fungi.

Salem S Salem,Omar M Ali,Amr H Hashem,Ahmed M Reyad,Kamel A Abd-Elsalam

doi:10.3390/jof8020126

Abstract

Mucormycosis is considered one of the most dangerous invasive fungal diseases. In this study, a facile, green and eco-friendly method was used to biosynthesize silver nanoparticles (AgNPs) using Pseudomonas indica S. Azhar, to combat fungi causing mucormycosis. The biosynthesis of AgNPs was validated by a progressive shift in the color of P. indica filtrate from colorless to brown, as well as the identification of a distinctive absorption peak at 420 nm using UV-vis spectroscopy. Fourier-transform infrared spectroscopy (FTIR) results indicated the existence of bioactive chemicals that are responsible for AgNP production. AgNPs with particle sizes ranging from 2.4 to 53.5 nm were discovered using transmission electron microscopy (TEM). Pattern peaks corresponding to the 111, 200, 220, 311, and 222 planes, which corresponded to face-centered cubic forms of metallic silver, were also discovered using X-ray diffraction (XRD). Moreover, antifungal activity measurements of biosynthesized AgNPs against Rhizopus Microsporus, Mucor racemosus, and Syncephalastrum racemosum were carried out. Results of antifungal activity analysis revealed that the biosynthesized AgNPs exhibited outstanding antifungal activity against all tested fungi at a concentration of 400 µg/mL, where minimum inhibitory concentrations (MIC) were 50, 50, and 100 µg/mL toward R. microsporus, S. racemosum, and M. racemosus respectively. In addition, the biosynthesized AgNPs revealed antioxidant activity, where IC50 was 31 µg/mL when compared to ascorbic acid (0.79 µg/mL). Furthermore, the biosynthesized AgNPs showed no cytotoxicity on the Vero normal cell line. In conclusion, the biosynthesized AgNPs in this study can be used as effective antifungals with safe use, particularly for fungi causing mucormycosis.

Highlights

Mucormycosis is a serious infection and needs to be treated with prescription antifungal medicine, usually amphotericin B, posaconazole, or isavuconazole [9].The increasing usage of antifungal medications has resulted in the emergence of fungal strains such as Candida albicans [10], Lichtheimia corymbifera, R. microsporus, R. arrhizus, and M. circinelloids that are resistant to the majority of antifungal treatments [11,12]
Green biosynthesis of AgNPs has risen in prominence as a potential alternative to chemical and physical techniques
The proteins or enzymes involved in cell-free filtrates of P. indica that change nitrate to nitrite, and reduced silver ions to silver in the metallic form, may be responsible for the synthesis of AgNPs

Summary

Introduction

Mucormycosis is a disease caused by a group of fungi called mucormycetes, which includes various genera such as Rhizopus, Mucor, Synsephalastrum, Absidia, and Cunninghamella [4,5]. These fungi invade people with a history of diabetes, stem cell transplants, cancer, injection drug use, skin injury due to surgery, burns, or wounds [6,7,8]. To combat drug-resistant fungus, novel antifungal medicines based on current biotechnology must be investigated

Methods

Discussion

Conclusion