鼠伤寒沙门菌pStSR100质粒对生物膜形成的影响

目的:鼠伤寒沙门菌在多种表面形成的生物膜对其致病性和引起食物中毒等方面起着重要作用,本研究探讨鼠伤寒沙门菌pStSR100质粒对细菌在不同材质表面生物膜形成的影响。方法:用LB(Luria-Bertani,LB)培养基和TSB(Tryptose Soya Broth,TSB)培养基分别将携带pStSR100质粒的野生株在96孔板与放置无菌小圆玻片的24孔板中静态培养48 h,用结晶紫半定量法确定生物膜形成的适宜培养基。将野生株与消除质粒的突变株,用结晶紫半定量法和激光共聚焦显微镜(Confocal Laser scanning microscopy,CLSM)观察其在聚苯乙烯培养板和小圆玻片表面形成生物膜的差异。结果:用LB培养时细菌生物膜的形成能力高于用TSB培养,LB培养基更适宜生物膜形成;结晶紫半定量法结果表明野生株比突变株在小圆玻片表面形成生物膜的能力明显增强,而在聚苯乙烯培养板表面两者则无明显差异;CLSM观察发现,野生株在小圆玻片表面形成融合成片的大克隆,突变株仅形成较小克隆。结论:鼠伤寒沙门菌pStSR100质粒能促进该菌在亲水性材质表面生物膜的形成,但其对该菌在疏水性材质表面生物膜的形成未见明显影响,这一新发现为进一步研究鼠伤寒沙门菌生物膜形成的调控机制,研制抗感染材料提供了理论和实验依据。

The Effect of Salmonella TyphimuriumpStSR100 Plasmid on Salmonella BiofilmFormation

Objective:The ability of Salmonella typhimurium biofilm formation on different surfaces contribute greatly to its pathogenicity, causing food poison and so on, our study was to investigate the effect of Salmonella typhimurium (S. typhimurium) pStSR 100 plasmid on the S. typhimuriumbiofilmformation on plastic and glass surfaces.Methods:Wild type strain carrying plasmid pStSR100 was cultured in LB or TSB in 96 wells and 24 wells with sterilized round glass discs submerged in the broth for 48 h to determine the optimum medium of biofilm formation using crystal violet semi-quantitative method. Wild type strain and pStSR100 deletion mutant strain were allowed to develop biofilm on plastic and glass discs surfaces, Crystal violet staining and Confocal Laser Scanning Microscopy (CLSM) were used to evaluate the effect of plasmid on S. typhimurium biofilm formation.Results:The ability of bacterial biofilm formation was better when cultured in LB, which is the optimum medium for Salmonella biofilm formation. Furthermore, when cultured in LB, the carrying plasmid wild type strain formed more biofilm on round glass discs surface compared to the mutant strain using Crystal violet semi-quantitative method; however, no difference was observed on plastic surface. When observed in CLSM, wild type strain tended to form more bigger colonies compared to the mutant strain on round glass discs surface.Conclusion:The carriage of plasmid pStSR100 leads to increased Salmonella typhimurium biofilm formation on hydrophilic material, however, no significant increased biofilm formation on hydrophobic material was observed. Here, we demonstrate a new link between plasmid carriage and biofilmformation on hydrophilic material, which can provide the theoretical and experimental basis for further studying on the regulatory mechanismof Salmonella biofilmformation and discovering new antibacterial materials.