桃柁酚对金黄色葡萄球菌生物膜及icaA表达的抑制作用

为研究桃柁酚对金黄色葡萄球菌生物膜及icaA表达的抑制作用,用微量肉汤稀释法测定桃柁酚对10株金黄色葡萄球菌浮游菌和生物膜的最小抑菌浓度和最小杀菌浓度,并利用激光共聚焦显微镜观察桃柁酚抑制生物膜的情况;通过实时荧光定量RT-PCR技术检测桃柁酚对细菌生物膜形成过程中相关基因的水平变化;采用斑点免疫印迹法检测细胞间多糖黏附素在生物膜形成过程中的作用。结果显示,桃柁酚对金黄色葡萄球菌浮游菌和生物膜的最小抑菌浓度值范围分别为1～2μg/mL和4～16μg/mL;能杀灭和清除已形成的生物膜;桃柁酚可通过影响agr和sar调控系统,抑制细胞间多糖黏附素合成基因icaA的表达进而抑制细胞间多糖黏附素的合成。表明桃柁酚能有效抑制金黄色葡萄球菌浮游菌和生物膜,是一种抑制金黄色葡萄球菌生物膜的有效药物。

Inhibitory effects of totarol on biofilm formation and icaA expression of Staphylococcus aureus

To evaluate the inhibitory effects of totarol on icaA expression and biofilm formation of Staphylococcus aureus,minimum inhibitory concentrations and minimum bactericidal concentrations of totarol were determined for 10 strains of S.aureus grown in suspension and biofilm using microbroth dilution method.Inhibition of totarol on biofilm formation was observed by using laser scanning confocal microscope.Real-time RT-PCR analysis was performed to determine the effect of totarol on the expression of the biofilm-related genes.The effect of polysaccharide intercellular adhesin on biofilm formation was studied using dot-blot assay.Totarol showed antimicrobial activity against both planktonic and biofilm cultures of S.aureus strains,with minimum inhibitory concentrations ranged from 1 to 2 μg/mL and 4 to 16 μg/mL,respectively.Laser scanning confocal microscopy images indicated that totarol was able to detach and kill existing biofilms.Totarol may have an influence on agrA and sarA,inhibit icaA,and then inhibit polysaccharide intercellular adhesin.Thus,totarol was an effective antimicrobial agent to combat S.aureus biofilms.