铜绿假单胞菌中MuxABC-OpmB调节基因的筛选及研究

发布时间：2018-05-27 06:45

  本文选题：铜绿假单胞菌 + MuxABC-OpmB　； 参考：《西北大学》2012年硕士论文

【摘要】：铜绿假单胞菌作为一种常见的条件致病菌,本身具有内在耐药性和获得性耐药性。由于抗生素的不合理使用,细菌耐药现象越来越突出,给临床治疗带来了极大的挑战。研究PA耐药机制对于控制PA感染是非常重要的。 RND外排泵与抗生素外排直接相关,参与了细菌包括毒性因子表达,QS系统,T3SS分泌系统,RsmA等多个生物学过程。MuxABC-OpmB是最近发现的PA中的一种外排泵。研究表明：MuxABC-OpmB与氨曲南,新生霉素,四环素,红霉素等抗生素抗性相关。PAO1(ΔMuxABC)中,细菌对Amp, Cb的敏感性降低,致病力下降。MuxABC-OpmB与抗生素抗性以及细菌致病性均有关系,对其调节因子的研究非常重要,但目前尚未有相关报道。 本研究以MuxABC-OpmB为对象,首先对PAO1(ΔMuxABC)中细菌耐药性及致病性的机理进行了进一步研究,发现引起细菌耐药性升高的原因是由于超广谱β-内酰胺酶(ESBLs)活性的升高引起的,而致病能力的降低可能与生物被膜的减少相关。 其次,利用转座突变的方法在PAO1全基因组的水平上筛选MuxABC的调节基因,共得到15株影响MuxABC的突变体,随机PCR测序确定了10个抑制子,4个激活子,这些调节基因从ClassⅠ至ClassⅣ均有分布,它们不同程度的调节了MuxABC的表达。 通过基因互补,变变体构建,抗生素敏感性及相关毒性因子测定,细菌运动性分析等手段对PA2581进行了深入研究,发现PA2581为MuxABC外排泵抑制子,PA2581的缺失导致MuxABC外排泵表达的增强,从而引起相应的表型变化。其调节方式有待进一步研究。 本研究对于深入了解铜绿假单胞菌群体耐药机制,寻找潜在药物作用靶点,开发新型抗菌药物具有重要意义。
[Abstract]:Pseudomonas aeruginosa, as a common conditional pathogen, has intrinsic and acquired resistance. Because of the irrational use of antibiotics, the phenomenon of bacterial drug resistance is becoming more and more prominent, which brings great challenges to clinical treatment. It is very important to study the mechanism of PA resistance to control PA infection. RND efflux pump is directly related to antibiotic efflux. It is involved in many biological processes, such as T3SS secretion system and so on. MuxABC-OpmB is one of the recently discovered PA efflux pumps. The results showed that the sensitivity and pathogenicity of bacteria to AMPC and CB decreased, and the resistance to antibiotics, such as antibiotic resistance, antibiotic resistance and pathogenicity were related to the resistance to amtreonam, neomycin, tetracycline, erythromycin and other antibiotics (螖 MuxABC), the results showed that the sensitivity of bacteria to AMPC and CB was decreased, and the pathogenicity of bacteria was also related to the resistance to antibiotics and the pathogenicity of bacteria. The study of its regulatory factors is very important, but there are no related reports. In this study, the mechanism of bacterial resistance and pathogenicity in PAO1 (螖 MuxABC) was further studied. It was found that the increase of bacterial resistance was caused by the increase of extended-spectrum 尾 -lactamase (ESBLs) activity. The decrease of pathogenicity may be related to the decrease of biofilm. Secondly, MuxABC regulatory genes were screened at the level of PAO1 genome by transposable mutation method. A total of 15 mutants affecting MuxABC were obtained. 10 suppressor and 4 activators were sequenced by random PCR sequencing. These regulatory genes were distributed from Class 鈪，

本文编号：1940917