培养条件对奇异变形杆菌生物膜生长的影响

采用改良微孔板培养,结晶紫染色、平板计数以及电镜扫描方法研究不同初始菌浓度、培养环境(温度、气体环境)、培养基成分(pH、氯化钠浓度、碳源种类和浓度),培养基用量及接触材料对奇异变形杆菌(Proteus mirabilis,P. mirabilis)生物膜生长的影响。经过24 h培养,初始菌浓度10 CFU/cm²时,生物膜形成量较低,初始菌浓度10²~10⁸ CFU/cm²时,生物膜形成量明显;37 ℃有氧条件适宜P. mirabilis生物膜形成;培养基组成(2.0% NaCl,1.0%麦芽糖,pH8.0)和加倍用量对P. mirabilis生物膜形成具有明显的促进作用;粗糙的木制表面最易使P. mirabilis粘附并形成生物膜,硅胶次之,聚丙烯塑料和盖玻片表面比较光滑,菌体不易粘附,生物膜难以形成;不同接触材料形成的P. mirabilis生物膜结构和形态不同,硅胶上生物膜为蘑菇状,盖玻片上生物膜成扁平状。本文研究结果可为食品生产加工过程中P. mirabilis污染防控提供理论依据和技术支撑。

Effect of Culture Conditions on the Biofilm of Proteus mirabilis

The effects of different initial bacteria concentration, culture environment (temperature, gas environment), medium composition (pH value, NaCl concentration, carbon source type and concentration), medium dosage and contact materials on biofilm formation of Proteus mirabilis were investigated. Microporous plate culture, the crystal violet staining, plate counting and scanning electron microscopy were used to evaluate the effects of different culture conditions on biofilm formation. After 24 h of culture, the amount of biofilm formation was relatively low at the initial bacterial concentration of 10 CFU/cm2 whereas the amount of biofilm formation was dominant at the initial concentration of 102~108 CFU/cm2.The aerobic condition at 37℃ was adaptable for the formation of Proteus mirabilis biofilm. The culture medium composition with 2.0% NaCl and 1.0% maltose at pH8.0 and double quantity of the medium promoted obviously the formation of Proteus mirabilis biofilm. Among the four contact materials, the surface with roughed wood chip was the easiest material to form biofilm of Proteus mirabilis, followed by silica gel. The surface with polypropylene plastic and cover glass plate were not easy to form Proteus mirabilis biofilm due to its smoothness to adhere. Scanning electron microscopy investigation showed that the structure of Proteus mirabilis biofilm formed was various with different contact materials. On the silica gel, the biofilm of Proteus mirabilis was a mushroom-like while on the cover glass plate it was a flat layer. These results provide a theoretical and technical basis for prevention and control of Proteus mirabilis contamination in the food production and processing line.