Effect of Green‐Synthesized Silver Nanoparticles From Nepeta pogonosperma and Astrodaucus persicus on the Reduction of Bap Gene Expression in Strong Biofilm‐Producing Acinetobacter baumannii Clinical Isolates

Given the critical role of the bap gene in biofilm formation of Acinetobacter baumannii, this study aimed to evaluate the efficacy of green-synthesized silver nanoparticles (AgNPs) derived from Nepeta pogonosperma and Astrodaucus persicus (Boiss) in reducing the expression of this gene and inhibiting biofilm production in clinical isolates of A. baumannii. AgNPs were synthesized using the leaf extracts of the plants and characterized using standard techniques. The minimum inhibitory concentration of the AgNPs was determined by the microbroth dilution method. Biofilm production and the anti-biofilm effects of the nanoparticles were assessed using a microtiter plate assay. Quantitative real-time PCR was employed to evaluate bap gene expression levels before and after treatment with the AgNPs. The AgNPs significantly inhibited biofilm formation in A. baumannii. Furthermore, a marked reduction in bap gene expression was observed following treatment. Moreover, 90% and 10% of the isolates showed up to 60% and 61%-80% of biofilm disruption after treatment with A. persicus AgNP, respectively. In addition, 80%, 15%, and 5% of the isolates showed up to 60%, 61%-80%, and more than 80% of biofilm disruption after treatment with N. pogonosperma AgNP, respectively. Green synthesis of silver nanoparticles represent a promising strategy to counteract antimicrobial resistance. The AgNPs investigated in this study demonstrated significant potential in inhibiting biofilm formation and reducing bap gene expression in strong biofilm-producing clinical isolates of A. baumannii. Further research is warranted to elucidate the underlying mechanisms and optimize the clinical application of these nanoparticles.