Abstract
Emerging antibiotic-resistant bacteria result in increased mortality and have negative economic impacts. It is necessary to discover new strategies to create alternative antibacterial agents that suppress the bacterial resistance mechanism and limit the spread of serious infectious bacterial diseases. Silver nanoparticles may represent a new medicinal agents as alternative antibiotics affect different bacterial mechanisms such as virulence and resistance. In addition to that of silver nitrate (AgNO3) and ampicillin, for the first time, the inhibitory effect of silver nanoparticles synthesized usingDesertifilumsp. (D-SNPs) was evaluated against five pathogenic bacteria using the agar well diffusion method. Also, the influence of D-SNPs and AgNO(3)on bacterial antioxidant and metabolic activities was studied. The antibacterial activity of D-SNPs and AgNO(3)against methicillin-resistantStaphylococcus aureus(MRSA) strains was studied at the morphological and molecular level. D-SNPs and AgNO(3)have the ability to inhibit the growth of the five bacterial strains and resulted in an imbalance in the CAT, GSH, GPx and ATPase levels.MRSAtreated with D-SNPs and AgNO(3)showed different morphological changes such as apoptotic bodies formation and cell wall damage. Moreover, both caused genotoxicity and denaturation ofMRSAcellular proteins. Additionally, TEM micrographs showed the distribution of SNPs synthesized byMRSA. This result shows the ability ofMRSAto reduce silver nitrate into silver nanoparticles. These data indicate that D-SNPs may be a significant alternative antibacterial agent against different bacteria, especially MDR bacteria, by targeting the virulence mechanism and biofilm formation, leading to bacterial death.