Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
Department of Microbiology, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran.
Ann Clin Microbiol Antimicrob. 2023 Oct 5;22(1):89. doi: 10.1186/s12941-023-00639-2.
Biofilm formation by Pseudomonas aeruginosa (P. aeruginosa) is known to be characteristic of this organism. This bacterium is considered one of the most life-threatening bacteria and has been identified as a priority pathogen for research by WHO. Biofilm-producing P. aeruginosa is a concern in many parts of the world due to antibiotic resistance. Alginate also plays an important role in the biofilm formation of P. aeruginosa as well as the emergence of antibiotic resistance in biofilms. In addition, the systems of toxin-antitoxin( TA) play an important role in biofilm formation. Metal nanoparticle(NP) such as zinc oxide (ZnO) also have extensive biological properties, especially anti-biofilm properties. Therefore, this study was conducted in relation to the importance of zinc oxide nanoparticles (ZnO NPs) in biofilm formation and also the correlation of gene expression of TA systems in clinical isolates of P. aeruginosa.
A total of 52 P. aeruginosa isolates were collected from burns (n = 15), UTI (n = 31), and trachea (n = 6) in hospitals in Ilam between May 2020 and October 2020. Biofilm formation was assessed using a microtiter plate assay. MIC and sub-MIC concentrations of ZnO NPs (10-30 nm with purity greater than 99.8%) in P. aeruginosa were determined. Subsequently, biofilm formation was investigated using sub-MIC concentrations of ZnO NPs. Finally, total RNA was extracted and RT- qPCR was used to determine the expression levels of genes of mazEF, mqsRA, and higBA of TA systems.
Six isolates of P. aeruginosa were found to form strong biofilms. The results showed that ZnO NPs were able to inhibit biofilm formation. In our experiments, we found that the sub-MIC concentration of ZnO NPs increased the gene expression of antitoxins mazE and mqsA and toxin higB of TA systems treated with ZnO NPs.
In the present study, ZnO NPs were shown to effectively inhibit biofilm formation in P. aeruginosa. Our results support the relationship between TA systems and ZnO NPs in biofilm formation in P. aeruginosa. Importantly, the expression of antitoxins mazE and mqsA was high after treatment with ZnO NPs, but not that of antitoxin higA.
铜绿假单胞菌（P. aeruginosa）形成生物膜是其特征之一。这种细菌被认为是最具生命威胁的细菌之一，并被世界卫生组织确定为优先研究的病原体。由于抗生素耐药性，产生生物膜的铜绿假单胞菌在世界许多地方都令人担忧。此外，藻酸盐在铜绿假单胞菌生物膜的形成以及生物膜中抗生素耐药性的出现中也起着重要作用。此外，毒素-抗毒素（TA）系统在生物膜形成中也起着重要作用。金属纳米颗粒（NP）如氧化锌（ZnO）也具有广泛的生物学特性，特别是抗生物膜特性。因此，这项研究是关于氧化锌纳米颗粒（ZnO NPs）在生物膜形成中的重要性以及铜绿假单胞菌临床分离株中 TA 系统基因表达的相关性。
本研究于 2020 年 5 月至 10 月在伊拉姆的医院中收集了 52 株铜绿假单胞菌，分别来自烧伤（n=15）、尿路感染（n=31）和气管（n=6）。使用微量滴定板测定法评估生物膜形成。测定了铜绿假单胞菌中 ZnO NPs（纯度大于 99.8%，粒径 10-30nm）的 MIC 和亚 MIC 浓度。随后，使用 ZnO NPs 的亚 MIC 浓度研究生物膜形成。最后，提取总 RNA，使用 RT-qPCR 测定 TA 系统 mazEF、mqsRA 和 higBA 基因的表达水平。
发现 6 株铜绿假单胞菌形成强生物膜。结果表明，ZnO NPs 能够抑制生物膜形成。在我们的实验中，我们发现 ZnO NPs 的亚 MIC 浓度增加了经 ZnO NPs 处理的 TA 系统抗毒素 mazE 和 mqsA 以及毒素 higB 的基因表达。
本研究表明，ZnO NPs 可有效抑制铜绿假单胞菌生物膜形成。我们的结果支持 TA 系统与 ZnO NPs 在铜绿假单胞菌生物膜形成中的关系。重要的是，ZnO NPs 处理后抗毒素 mazE 和 mqsA 的表达水平较高，而抗毒素 higA 的表达水平则较低。
