金黄色葡萄球菌在静置和振荡培养条件下的生物被膜构造

Biofilm Architecture of Staphylococcus aureus during Static and Shaking Cultivation

目的:为了控制食品生产环境中金黄色葡萄球菌的生物被膜污染,研究其在不锈钢表面的生物被膜构造。方法:在细胞培养板中静置培养生物被膜,在三角瓶中振荡培养生物被膜。培养期间,分时段取样,使用活菌计数法测定生物被膜生物量,用扫描电镜观察生物被膜构造。结果:在静置条件下可较快形成生物被膜,生物量在16 h达到最大值7.73 lg(CFU/cm2),之后逐渐下降,48 h降至5.19 lg(CFU/cm)2;生物被膜在形成初期就呈多层细胞立体结构,细胞聚集体在不锈钢表面分布稠密。振荡条件下形成生物被膜较慢,生物量在48 h达到7.04 lg(CFU/cm2),此后基本维持不变;生物被膜在形成初期主要呈单层细胞平面结构,进入成熟期后,细胞聚集体层数依然较少,并且分布稀疏。结论:金黄色葡萄球菌在静置和振荡培养条件下生物被膜的发展动态和构造有明显差异,应制定不同的控制对策。

Objective： The architecture of biofilm formed by Staphylococcus aureus on the surface of stainless steel was studied to control the biofilm pollution in food proceeding environment. Methods： The static cultivation of biofilm was performed in cell culture plates, and the shaking cultivation was conducted in Erlenmeyer flasks. During cultivation,samples were collected at different time. The biofilm biomass was determined by viable count method, and the biofilm structure was observed using scanning electron microscopy. Results： Biofilm was formed quickly in static condition. Its biomass reached the maximum value 7.73 lg（CFU/cm^2） at 16 h and then gradually decreased, arriving at 5.19 lg（CFU/cm^2）at 48 h. During static cultivation, the initial biofilm existed in three-dimensional structure of multilayers of cells, and the cell aggregates were thick-set on the surface of stainless steel. The biofilm was developed slowly in shaking conditions.Its biomass reached 7.04 lg（CFU/cm^2） at 48 h, and afterwards it nearly maintained unchanged. During shaking cultivation, the initial biofilm was mainly composed of monolayer of cells in planar structure. Even after maturation, the cell aggregates were still relatively less than those in static conditions. Conclusion： The dynamic changes and architecture of biofilm formed by Staphylococcus aureus during static and shaking cultivation obviously varied. Therefore, different strategies should be made for controlling them.