苦参碱对奶牛乳房炎产膜表皮葡萄球菌Ⅰ类整合酶基因表达量的影响

Effects of matrine on classⅠintegrase gene expression in bovine mastitis Staphylococcus epidermidis biofilm

为探究苦参碱对产膜表皮葡萄球菌(Staphylococcus epidermidis,SE)Ⅰ类整合酶基因(class 1integrase gene,intI1)的影响,本试验采用二倍稀释法分别测定苦参碱、苦豆子碱、卡那霉素和头孢西汀对SE的最低抑菌浓度(MIC);利用棋盘滴定法测定4种药物对SE的联合作用的效果;用XTT法测定不同质量浓度下药物对产膜阳性菌株的抑菌效果并绘制其抑制曲线;采用荧光定量PCR方法分析药物对生物膜状态下intI1在mRNA水平表达的影响。结果显示:苦参碱、苦豆子碱、卡那霉素和头孢西汀对产膜阳性菌株的MIC分别是12.5g/L、20g/L、512mg/L、128mg/L;它们在亚抑菌浓度下均对产膜阳性菌株有一定的抑菌作用;取1/2MIC的药物质量浓度对产膜阳性菌株作用2h和4h,发现苦参碱作用4h后intI1基因表达量下调,表明苦参碱对在生物被膜状态下的SE中intI1在mRNA水平上有抑制作用,提示苦参碱对被膜状态下的SE的整合酶基因表达量有一定的抑制作用,从而影响整合子在生物被膜状态下捕获耐药基因的能力。

To explore the effects of matrine on class 1integrasegene（intI1）of integron from Staphylococcus epidermidis biofilm.In this study,we applied double dilution method tomeasure the MICs of matrine,alkaloids,kanamycin and cephalosporins on SE.And the checkerboard method was used to determine the combined effects of the drugs,inhibition curves of biofilm formation positive strains were measured at different drug concentrations by XTT,real-time PCR was applied to detect the effects of drugs on intI1 mRNA expression levels.The results showed that MICs of matrine,alkaloids,kanamycin and cephalosporins on SE were 12.5g/L,20g/L,512mg/L and 128mg/L,respectively.Drugs at sub-inhibitor concentrations have some effects on antibacterial function for SE biofilmformation.After a 1/2MIC drug concentration on SE biofilm for 2h and 4h,the result showed that intI1 can be down-regulated at 4h.This study demonstrate that matrine can down-regulate intI1,suggesting that matrine has certain inhibition function on intI1 of SE biofilm,thus affects the ability to trapping resistance genes in biofilmcells.