铁基纳米酶对鼠伤寒沙门菌生物被膜的影响

运用结晶紫染色定量法、生物被膜形态观察、生物被膜干重称量法、活菌定量计数法和细菌内活性氧检测法,评估氧化铁纳米酶和硫化铁纳米酶对鼠伤寒沙门菌生物被膜的影响及其机制.结果显示:鼠伤寒沙门菌S025株与这两类铁基纳米酶共孵育48h后,其生物被膜结晶紫染色吸光度值(A)、生物被膜厚度、生物被膜干重和活菌数量与未处理组相比均显著下降,活性氧水平显著上升,其中硫化铁纳米酶效果优于四氧化三铁纳米酶;在生物被膜形成后,加入铁基纳米酶处理0.5h、2h和12h,生物被膜结晶紫染色A值、生物被膜厚度、生物被膜干重和活菌数量与未处理组相比均显著下降,活性氧水平显著上升,硫化铁纳米酶效果同样优于四氧化三铁纳米酶.以上结果表明,铁基纳米酶通过调控鼠伤寒沙门菌胞内活性氧水平,不仅可以预防该菌的生物被膜形成,而且可以破坏已形成的生物被膜,本研究将有助于预防和治疗鼠伤寒沙门菌生物被膜引起的相关疾病.

Effects of Iron-based Nanozymes on S. typhimurium Biofilm

To evaluate the effect of iron-based nanozymes on the biofilm of S.typhimurium, the biofilms were detected by crystal violet staining method, biofilm integrity, biofilm biomass, bacterial activity, and the intracellular ROS levels of S.typhimurium S025. Our results showed that, after treatment with iron oxide (Fe₃O₄) nanozyme and iron sulfide (nFeS) nanozyme during biofilm formation for 48 h, the A₅₅₀ value, biofilm height, biofilm biomass, and bacteria viability were significantly decreased compared to the untreated group, but the intracellular ROS levels remarkably increased. Moreover, to determine whether there is a similar inhibitory effect on pre-formed biofilms, Fe3O4 nanozyme and nFeS nanozyme were incubated from the apical side of the biofilms for different time. As expected, both nanozymes appreciably destroyed the biofilms that had formed. Importantly, nFeS nanozyme showed better efficacy than Fe₃O₄ nanozyme in above biofilm treatment. Taken together, these findings clearly demonstrated that iron-based nanozymes, as a suitable agent, regulated intracellular ROS levels to prevent the biofilm formation of S.typhimurium and destroyed the matured biofilm, which is helpful to preventing and treating relevant diseases caused by biofilm of S.typhimurium.