金黄色葡萄球菌分离株的菌膜测定及其影响因素

采用96孔细胞培养板法,对10株不同来源的金黄色葡萄球菌分离株的菌膜形成能力进行调查,并研究外部环境因素对金黄色葡萄球菌菌膜形成的影响。首先以金黄色葡萄球菌标准菌株ATCC6538为模式菌株,确定了亲水性细胞培养板、培养48 h为适宜的菌膜体外培养条件。在此条件下测定了10株分离株的菌膜形成量,并研究了不同培养温度（25~46℃）和不同营养条件（葡萄糖和氯化钠）对菌膜形成的影响。结果显示,体外培养条件下,金黄色葡萄球菌普遍可以形成菌膜,10株菌中仅1株为菌膜阴性,不同菌株菌膜形成能力差异较大;较高的培养温度有利于菌膜的形成,有3株菌在46℃时菌膜形成量达到最大;0.5%葡萄糖和1%氯化钠的添加可显著改变各菌株的菌膜形成,葡萄糖倾向于促进临床分离株菌膜形成量的增加,而氯化钠倾向于促进食品分离株菌膜形成量的增加。这一结果,可以为实际环境中菌膜的预防及控制提供指导和方向,同时也说明金黄色葡萄球菌的菌膜形成存在着不同的调控模式。

Biofilm Testing and Effects of Environmental Factors on the Biofilm Formation of Staphylococcus aureus Isolates

10 strains of Staphylococcus aureus were cultured on the microtitre 96-well plate to investigate the biofilm characteristics and the effect of the environmental factors in the biofilm formation.The optimized incubation conditions including the application of the hydrophilic microtitre plates and 48 h of culture time were established using ATCC6538 as the standard strain.The biofilm production of 10 S.aureus isolates was determined,and the effect of culturing temperature（25~46 ℃） and nutrients（glucose and NaCl） on the biofilm formation was also investigated.The results showed that the biofilm was usually synthesized in the majority of S.aureus strains and only 1 out of 10 isolates was found negative（without mature biofilm）.Significant differences of the capability in the biofilm formation were indicated among different strains.Higher temperature could improve the biofilm formation of S.aureus and the maximum production of bioform was found in 3 out of the 10 isolates at 46 ℃.The supplementation of 0.5% glucose and 1% sodium chloride could significantly stimulate the biofilm production of S.aureus.Furthermore,it was obvious that the addition of glucose could enhance the biofilm formation in the clinically isolated strains while NaCl could improve that in the strains isolated from food samples.These results implied that different regulating pathways were involved in the biofilm formation and this study might provide useful guidance for the prevention and control of the bacterial contamination.