生物膜铜绿假单胞菌群体感应系统对其AmpC基因表达调控的研究

发布时间：2018-03-19 06:27

  本文选题：铜绿假单胞菌　切入点：生物膜　出处：《青岛大学》2009年硕士论文　论文类型：学位论文

【摘要】： 目的:研究铜绿假单胞菌(PA)在抗生素诱导状态下,产酶基因AmpC在浮游和生物膜状态下的表达差异,群体感应(QS)系统对产酶基因AmpC表达的影响。 方法:改良的平板法建立PA生物膜模型,抗生素诱导浮游菌和生物被膜菌AmpC基因表达,采用实时荧光定量PCR方法测定PAO1、PAO1加用QS抑制剂(呋喃酮C-30)及QS系统缺陷菌株的AmpC基因表达水平。 结果:抗生素诱导前,PAO1浮游菌和生物膜菌的AmpC基因表达均较低,诱导后AmpC基因表达均明显上调。运用产最大AmpC酶活性的浓度的抗生素诱导后,亚胺培南和头孢他定诱导的生物膜菌的AmpC基因表达量均高于其诱导的浮游菌。在浮游和生物膜状态下,亚胺培南诱导PAO1的AmpC基因表达量均高于头孢他定。PAO1在抗生素诱导同时加用呋喃酮C-30后,浮游菌和生物被膜菌的AmpC基因表达水平均较不加用呋喃酮C-30下调,生物被膜菌下调的程度大于浮游菌,两者差别有统计学意义(P＜0.05)。在浮游和生物膜状态运用抗生素诱导,QS系统缺陷菌株PAO-MW1、PAO-JP1的AmpC基因表达水平均较PAO1低。 结论:生物膜PA较浮游菌更易被诱导产生AmpC酶,亚胺培南的诱导能力高于头孢他定。PA的QS系统直接或间接调控AmpC基因的诱导表达,不同状态下QS系统发挥调控作用的水平不同可能是生物被膜菌较浮游菌易诱导产酶原因之一。
[Abstract]:Aim: to study the difference of AmpC expression between plankton and biofilm induced by Pseudomonas aeruginosa (PAA) and the effect of population sensing system on the expression of AmpC. Methods: PA biofilm model was established by modified plate method. AmpC gene expression was induced by antibiotics in phytoplankton bacteria and biofilm bacteria. The expression of AmpC gene in PAO1-PAO1 + QS inhibitor (furanone C-30) and QS system deficient strains was determined by real-time fluorescence quantitative PCR. Results: the AmpC gene expression of PAO1 and biofilm bacteria was lower and the expression of AmpC gene was up-regulated after antibiotic induction. The expression of AmpC gene in biofilm bacteria induced by imipenem and ceftazidine was higher than that in phytoplankton induced by imipenem and ceftazidine. The expression of AmpC gene in PAO1 induced by imipenem was higher than that in ceftazidine. PAO1. The expression level of AmpC gene in phytoplankton and biofilm bacteria was lower than that in non-treated furanone C-30. The down-regulation degree of biofilm bacteria was higher than that of phytoplankton, and the difference was statistically significant (P < 0.05). The AmpC gene expression level of PAO-MW1 PAO-JP1 was lower than that of PAO1 in phytoplankton and biofilm status. Conclusion: the biofilm PA is more easily induced to produce AmpC than that of phytoplankton, and imipenem can directly or indirectly regulate the expression of AmpC gene in the QS system of cefatadine. Different levels of QS system regulation may be one of the reasons why biofilm bacteria can induce enzyme production more easily than phytoplankton bacteria.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R378

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