Evaluation of the antimicrobial potency of silver nanoparticles biosynthesized by using an endophytic fungus, Cryptosporiopsis ericae PS4

Abstract

In the present study, silver nanoparticles (AgNPs) with an average particle size of 5.5 ± 3.1 nm were biosynthesized using an endophytic fungus Cryptosporiopsis ericae PS4 isolated from the ethno-medicinal plant Potentilla fulgens L. The nanoparticles were characterized using UV-visible spectrophotometer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), selective area electron diffraction (SAED), and energy dispersive X-ray (EDX) spectroscopy analysis. Antimicrobial efficacy of the AgNPs was analyzed singly and in combination with the antibiotic/antifungal agent chloramphenicol/fluconazole, against five pathogenic microorganisms--Staphylococcus aureus MTCC96, Salmonella enteric MTCC735, Escherichia coli MTCC730, Enterococcus faecalis MTCC2729, and Candida albicans MTCC 183. The activity of AgNPs on the growth and morphology of the microorganisms was studied in solid and liquid growth media employing various susceptibility assays. These studies demonstrated that concentrations of AgNPs alone between 10 and 25 μM reduced the growth rates of the tested bacteria and fungus and revealed bactericidal/fungicidal activity of the AgNPs by delaying the exponential and stationary phases. Examination using SEM showed pits and ruptures in bacterial cells indicating fragmented cell membrane and severe cell damage in those cultures treated with AgNPs. These experimental findings suggest that the biosynthesized AgNPs may be a potential antimicrobial agent.

A One-Pot Synthesis and Characterization of Antibacterial Silver Nanoparticle–Cellulose Film

“…Studies have found that Ag-NPs with a size of 5-20 nm had greater antibacterial activities [2][3][4]. Currently, the widely recognized antibacterial mechanisms of Ag-NPs include disrupting the normal function of the cell wall [5], interacting with the lipid components of the cell membrane to impede its normal function [6][7][8][9][10], inducing ROS free radicals to damage the cell membrane [11][12][13], damaging the DNA structure and inhibiting its related functions [14][15][16], binding with sulfhydryl groups of enzyme proteins to make cell inactive, and so on [17,18]. Ag-NPs inhibits the characteristics of simple preparation, broad-spectrum antibacterial, strong sterilization, and less prone to emerge drug resistance, which prompted it to be used as an antibacterial agent added to ceramics [19], coatings [20], textiles [21], films [22,23], and other raw materials to fabricate antibacterial materials.…”

Certain Aspects of Silver and Silver Nanoparticles in Wound Care: A Minireview

“…It is a result from their evolutionary processes occurring in the course of an antibiotic treatment. The resistant bacteria survive medical treatment and pass this trait to future generations [1,2].…”

Nanosilver: new ageless and versatile biomedical therapeutic scaffold

“…However, complete inhibition of the growth of C. albicans MTCC183 was found at a concentration of 10 μM AgNPs. 264 A more recent report showed that AgNPs (spherical, 1-40 nm) had excellent antifungal activity against R. solani cultures by inhibiting 83% of the mycelium growth at 25 μg/mL concentration. 265 In another study, several essential oils were tested for their antifungal activity.…”