Green-Synthesized Silver Nanoparticles as a Potent Synergist to Antibiotics for Combating Pathogenic E. coli and Other Resistant Bacteria

The emergence of multidrug-resistant (MDR) bacterial strains represents a critical challenge to public health worldwide. In this study, we report the biosynthesized of silver nanoparticles (AgNPs) using Trigonella foenum-graecum (Fenugreek) seed extract and evaluate their antibacterial efficacy against MDR strains of Escherichia coli, Salmonella typhimurium, Listeria monocytogenes, and Staphylococcus epidermidis. Additionally, AgNPs were synthesized using extracts from other plants, including Nigella sativa (Black seed) and Cucurbita pepo (Pumpkin), for comparative analysis. The green synthesis AgNPs were characterized using FTIR and TEM, confirming spherical morphology and polydispersity, with an average size of particle (28.63 nm). FTIR analysis demonstrated the existence of galactomannans, other polysaccharides, and several functional groups such as polyphenols, flavonoids, and alcohols in the reduction and stabilization processes, with the carbonyl group acting as a capping agent. Antibacterial assays, including well diffusion, disc diffusion, and MIC/MBC determination, revealed substantial inhibitory effects. Notably, combining fenugreek AgNPs with conventional antibiotics such as ciprofloxacin and streptomycin enhanced antibacterial efficacy, suggesting a synergistic effect. In comparison, while AgNPs synthesized from black seed and pumpkin also exhibited antibacterial activity, the fenugreek-derived AgNPs demonstrated the most promising results in terms of efficacy. In conclusion, green-synthesized AgNPs, particularly those derived from fenugreek extract present a promising, adjuvants to traditional antibiotics in combating antimicrobial resistance. Their synergistic potential with antibiotics offers a potent strategy for reviving the efficacy of existing antimicrobials.