Ghadimi Narges, Asadpour Leila, Mokhtary Masoud
Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran.
Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran.
Microb Pathog. 2025 Feb;199:107241. doi: 10.1016/j.micpath.2024.107241. Epub 2024 Dec 21.
In the present study, we investigate the effect of FeO nanoparticles conjugated with ursolic acid (FeONPs@UA) on inhibiting the growth, biofilm-forming ability and efflux pump activity in clinical isolates of Pseudomonas aeruginosa with multiple drug resistance.
Iron oxide NPs conjugated with ursolic acid (FeONPs@UA) were synthesized. Physicochemical features of the NPs were studied by FT-IR, XRD, EDAX, and TEM. The antibacterial and antibiofilm effects of FeONPs@UA against P. aeruginosa isolates were determined by broth microdilution and microtiter plate methods, respectively. The efflux pump inhibitory effect of FeONPs@UA was determined using Cartwheel method and through determining the expression level of efflux pump genes, including mexA and oprD in selected P. aeruginosa isolates treated with sub-MIC concentration of FeONPs@UA by real-time PCR.
In investigating the antimicrobial effect of FeONPs@UA, the MIC of these nanoparticles varied between 0.19 and 0.78 mg/mL and in the study of the anti-biofilm effect of FeONPs@UA, it caused a 68-75 % decrease in biofilm formation compared to the control. Moreover, in the Cartwheel test, the anti-efflux effect of these nanoparticles was confirmed at 1/4-MIC concentrations, and the expression of mexA and oprD genes was reduced in bacteria treated with FeONPs@UA compared to the control.
According to the results, the use of FeONPs@UA can provide a basis for the development of new treatments against drug-resistant bacteria in P. aeruginosa. This substance can improve the concentration of antibiotics in bacterial cells and increase their effectiveness by inhibiting the efflux in P. aeruginosa isolates.
在本研究中，我们探究了熊果酸共轭的FeO纳米颗粒（FeONPs@UA）对多重耐药铜绿假单胞菌临床分离株生长、生物膜形成能力及外排泵活性的抑制作用。
合成了熊果酸共轭的氧化铁纳米颗粒（FeONPs@UA）。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、能谱分析（EDAX）和透射电子显微镜（TEM）研究了纳米颗粒的物理化学特性。分别采用肉汤微量稀释法和微量滴定板法测定FeONPs@UA对铜绿假单胞菌分离株的抗菌和抗生物膜作用。采用车轮法并通过实时聚合酶链反应（PCR）测定在亚最小抑菌浓度（sub-MIC）的FeONPs@UA处理的选定铜绿假单胞菌分离株中外排泵基因（包括mexA和oprD）的表达水平，以此确定FeONPs@UA的外排泵抑制作用。
在研究FeONPs@UA的抗菌作用时，这些纳米颗粒的最低抑菌浓度（MIC）在0.19至0.78毫克/毫升之间，在研究FeONPs@UA的抗生物膜作用时，与对照组相比，其生物膜形成减少了68%-75%。此外，在车轮试验中，这些纳米颗粒在1/4-MIC浓度下的抗外排作用得到证实，与对照组相比，用FeONPs@UA处理的细菌中mexA和oprD基因的表达降低。
根据结果，FeONPs@UA的使用可为开发针对铜绿假单胞菌耐药菌的新疗法提供依据。该物质可提高抗生素在细菌细胞内的浓度，并通过抑制铜绿假单胞菌分离株的外排作用来提高其有效性。
