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细菌的群体感应及特异基因表达调控在细菌生物被膜形成中有十分重要的作用。luxS,agr均是表皮葡萄球菌群体感应调控中的关键基因,RNAⅢ是agr系统的效应器分子。为了评估鱼腥草素钠及其与红霉素联用对产膜表皮葡萄球菌转录水平的影响,采用连续稀释法测定鱼腥草素钠、红霉素、万古霉素对表皮葡萄球菌的MIC;荧光定量PCR测定鱼腥草素钠及其与红霉素联用、万古霉素、红霉素等对表皮葡萄球菌作用后不同时间段luxS,agr/RNAⅢ的转录水平。结果表明1/2MIC,1/4MIC鱼腥草素钠,1/2MIC鱼腥草素钠+1/2MIC红霉素,1/4MIC鱼腥草素钠+1/4MIC红霉素,1/8MIC鱼腥草素钠+1/8MIC红霉素等在作用于ATCC 35984伊始,就可迅速上调luxS的表达,与阴性对照相比,存在显著差异(P<0.05);在作用6,12,48h后,鱼腥草素钠依然存在对luxS的上调作用。鱼腥草素钠在MIC,1/2MIC浓度时对agr表达均有显著下调作用(P<0.05),1/2MIC鱼腥草素钠与1/2MIC红霉素联用、1/4 MIC鱼腥草素钠与1/4MIC红霉素联用,在作用6,12,24 h等时间段对agr表达的下调作用也很显著(P<0.05)。鱼腥草素钠在MIC浓度时,对RNAⅢ表达亦有显著下调作用(P<0.05),1/2MIC鱼腥草素钠与1/2MIC红霉素联用对RNAⅢ表达的下调效果也很显著(P<0.05)。提示鱼腥草素钠及其与红霉素联用,可以迅速上调表皮葡萄球菌luxS转录水平的表达,在特定浓度下可下调agr/RNAⅢ的表达,具有抑制表皮葡萄球菌生物被膜菌之间的相互黏附聚集、抑制膜内营养和输水通道的形成、阻止膜内细菌脱离、并抑制细菌外毒素形成等作用的可能。
Bacterial population induction and regulation of specific gene expression in the formation of bacterial biofilm has a very important role. luxS and agr are the key genes in the induction of population of Staphylococcus epidermidis. RNA Ⅲ is the effector molecule of agr system. In order to evaluate the effect of sodium houttuyfonate and its combination with erythromycin on the transcriptional level of Staphylococcus epidermidis, continuous dilution method was used to determine the MICs of sodium houttuyfonate, erythromycin and vancomycin against Staphylococcus epidermidis ; Fluorescence quantitative PCR determination of sodium houttuyfonate and its combination with erythromycin, vancomycin, erythromycin and other effects of Staphylococcus epidermidis different stages of luxS, agr / RNA Ⅲ transcription level. The results showed that 1 / 2MIC, 1 / 4MIC houttuynin sodium, 1 / 2MIC sodium houttuyfonate + 1 / 2MIC erythromycin, 1 / 4MIC houttuynin sodium 1 / 4MIC erythromycin, 1/8 MIC Sodium houttuyfonate + 1 / 8MIC erythromycin could rapidly increase luxS expression at the beginning of ATCC 35984, which was significantly different from that of the negative control (P <0.05); at 6,12,48h Houttuynin sodium still has an up-regulation of luxS. Houttuyfonate sodium had significant down-regulation of agr expression at MIC and 1 / 2MIC concentrations (P <0.05), 1 / 2MIC sodium houttuyfonate combined with 1 / 2MIC erythromycin, and 1/4 MIC fish Sodium Houttuyfonate combined with 1/4 MIC erythromycin had a significant down-regulation of agr expression at 6, 12, 24 h (P <0.05). Sodium houttuyfonate also significantly down-regulated the expression of RNAⅢ at the MIC concentration (P <0.05). The combination of 1 / 2MIC sodium houttuyfonate and 1 / 2MIC erythromycin also significantly down-regulated the expression of RNAⅢ (P <0.05). It suggested that sodium houttuyfonate and its combination with erythromycin can rapidly up-regulate the luxS transcriptional level of Staphylococcus epidermidis and down-regulate the expression of agr / RNAⅢ at a specific concentration, and inhibit the growth of S. epidermidis biofilms Mutual adhesion and aggregation, inhibit the formation of membrane nutrients and water channels to prevent bacterial detachment within the membrane, and inhibit the formation of bacterial exotoxin may be the role.