Therapeutic potential of green-synthesized silver nanoparticles: Combating biofilms of multidrug-resistant Staphylococcus aureus RM-Ph8 and modulating the immune response in the liver tissue of rats.

Abstract

Background and aim: The emergence of multidrug-resistant Staphylococcus aureus (MRSA) strains poses a significant threat to healthcare settings. Although various studies have explored alternative antibiotics, discovering novel therapeutic agents remains crucial. This study aimed to synthesize green silver nanoparticles (AgNPs) as bactericidal agents, identify a multidrug-resistant isolate of Staphylococcus aureus, and explore their biofilm formation ability. To estimate the role of phyto-AgNPs in the perfection of immune markers and healing hepatic lesions in vivo.

Materials and methods: The clinical isolate of MRSA was identified using 16S rRNA New green AgNPs derived from Artemisia annua extract were synthesized. The nanoparticles (NPs) were characterized, and their minimum inhibitory concentration was estimated for fighting MRSA biofilm. A study was conducted on rats to evaluate the effect of new NPs on their immune response to MRSA infection.

Results: The new clinical isolate of MRSA RM-Ph8 was identified by molecular phylogenetic analysis as S. aureus, and 16S rRNA sequence analysis confirmed that the new strain was similar to S. aureus with 98.12% identity with accession number OQ421819. The FTIR of the new phyto-AgNPs displayed different functional groups that work as reducing silver nitrate agents. Transmission electron microscopy and scanning electron microscopy images showed spherical particles with an average diameter of 6-28 nm smaller. The chemical method led to complete cell destruction of the multidrug strain within 24 h. Biofilm formation showed that the new MRSA clinical strain was strongly adherent (88%). Notably, the phyto-AgNPs exhibited significant bactericidal activity against the new MRSA strain, with an MIC of up to 50 mg/mL. Moreover, phyto-AgNPs significantly decreased reversed MRSA-induced liver and kidney function impairment, with improvement in both the histopathological lesions and immune histochemical expression of tumor necrosis factor-α and inducible nitric oxide synthase at p < 0.05 compared with the untreated group.

Conclusion: Green AgNPs are a promising therapeutic approach against multidrug-resistant bacterial infections, surpassing the effectiveness of conventional antibiotics.