Combination of AgNPs and Domiphen is Antimicrobial Against Biofilms of Common Pathogens

Longhao Hu,1,* Xi Yang,2,3,* Jing Yin,1 Xuan Rong,1 Xinlei Huang,1 Peiquan Yu,3 Zhiqiang He,1 Yi Liu1– 3 1Department of Biophysics, School of Life Sciences, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People’s Republic of China; 2School of Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People’s Republic of China; 3Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yi LiuDepartment of Biophysics, School of Life Sciences, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People’s Republic of ChinaTel/Fax +86-516-83262084Email cbpeliuyinew@163.comPurpose: The aim was to evaluate the antimicrobial potential of AgNPs synthesized with Artemisia argyi leaf extract and investigate the antimicrobial synergistic effects of AgNPs combined with domiphen and provide an efficient and broad-spectrum combination drug strategy.Methods: AgNPs synthesized with Artemisia argyi leaf extract were studied using UV–vis spectroscopy, FTIR spectroscopy and particle size analysis. Then, Artemisia argyi leaf extract-synthesized AgNPs and domiphen were tested against Acinetobacter baumannii (ATCC 19606), Staphylococcus aureus (ATCC 6538), Escherichia coli (8099) and Candida albicans (ATCC 10231), respectively. Then, we explore synergistic antimicrobial effect and synergistic anti-biofilm effect through combined drug susceptibility test and combined drug minimum biofilm eradication concentration (MBEC50) test.Results: Characteristic absorption bands of AgNPs were found near 430 nm in the UV–vis spectrum. Particle size analysis results revealed that the average particle size of Artemisia argyi leaf extract-synthesized AgNPs was 77.6 nm. Artemisia argyi leaf extract-synthesized AgNPs showed high antimicrobial activity against the above four strains. Minimum inhibitory concentration (MIC) of Artemisia argyi leaf extract-synthesized AgNPs against strains was 1 μg/mL for Acinetobacter baumannii, 2 μg/mL for Staphylococcus aureus, Escherichia coli and Candida albicans. MBEC50 of Artemisia argyi leaf extract-synthesized AgNPs against strains was 2 μg/mL for Acinetobacter baumannii, 4 μg/mL for Staphylococcus aureus, 1/2 μg/mL for Escherichia coli and 2 μg/mL for Candida albicans. The combination of Artemisia argyi leaf extract-synthesized AgNPs and domiphen has synergistic antimicrobial effect and synergistic anti-biofilm effect. Fractional inhibitory concentration (FIC) was ≤ 0.5.Conclusion: Artemisia argyi leaf extract-synthesized AgNPs had antimicrobial activity against the above four strains. The combination of Artemisia argyi leaf extract-synthesized AgNPs and domiphen has synergistic antimicrobial effects to reduce the dosage of each antimicrobial drugs. Artemisia argyi leaf extract-synthesized AgNPs and domiphen have synergistic anti-biofilm effects.Keywords: AgNPs, domiphen, synergy, pathogenic biofilm, combination medication