Biosynthesized silver nanoparticles from Gelediella acerosa as a potent antibacterial agent against Multidrug-resistant wound isolates.

Abstract

Multidrug-resistant (MDR) bacteria pose a major global health threat, necessitating the development of novel therapeutic strategies for wound infections. Gelidiella acerosa (G. acerosa), a red marine alga rich in bioactive compounds, was investigated for the green synthesis of silver nanoparticles (AgNPs) and their pharmacological potential against MDR bacterial pathogens. GC-MS analysis confirmed the presence of bioactive phytoconstituents in the aqueous extract of G. acerosa. The synthesized AgNPs were characterized using UV-Vis spectroscopy, FT-IR, SEM, XRD, EDX-mapping, AFM, DLS, and zeta potential analyses. Antibacterial activity was evaluated by zone-of-inhibition, minimum inhibitory concentration, minimum bactericidal concentration, AO/PI confocal imaging, scanning electron microscopy, and protein leakage assays. Characterization confirmed the formation of stable, crystalline, spherical AgNPs with a surface plasmon resonance peak at 417 nm, a hydrodynamic diameter of 172.3 nm (PDI 0.3133), and a zeta potential of 24.94 mV. Acinetobacter baumannii_SN1 and Pseudomonas aeruginosa_SN2 isolated from wound infections were identified by 16S rRNA gene sequencing. The biosynthesized AgNPs exhibited significant antioxidant, antidiabetic, and antibacterial activities against both MDR isolates. Mechanistic studies demonstrated increased membrane permeability, disruption of bacterial membrane integrity, and enhanced protein leakage following AgNPs treatment. The biosynthesized AgNPs exhibited potent antibacterial activity against multidrug-resistant wound pathogens by disrupting bacterial membrane integrity, along with significant antioxidant and antidiabetic properties. These findings suggest that G. acerosa AgNPs represent a promising alternative therapeutic strategy for the management of MDR bacterial wound infections.