本文選題：銅綠假單胞菌 + MuxABC-OpmB��； 參考：《西北大學》2012年碩士論文

【摘要】：銅綠假單胞菌作為一種常見的條件致病菌,本身具有內(nèi)在耐藥性和獲得性耐藥性。由于抗生素的不合理使用,細菌耐藥現(xiàn)象越來越突出,給臨床治療帶來了極大的挑戰(zhàn)。研究PA耐藥機制對于控制PA感染是非常重要的。 RND外排泵與抗生素外排直接相關(guān),參與了細菌包括毒性因子表達,QS系統(tǒng),T3SS分泌系統(tǒng),RsmA等多個生物學過程。MuxABC-OpmB是最近發(fā)現(xiàn)的PA中的一種外排泵。研究表明：MuxABC-OpmB與氨曲南,新生霉素,四環(huán)素,紅霉素等抗生素抗性相關(guān)。PAO1(ΔMuxABC)中,細菌對Amp, Cb的敏感性降低,致病力下降。MuxABC-OpmB與抗生素抗性以及細菌致病性均有關(guān)系,對其調(diào)節(jié)因子的研究非常重要,但目前尚未有相關(guān)報道。 本研究以MuxABC-OpmB為對象,首先對PAO1(ΔMuxABC)中細菌耐藥性及致病性的機理進行了進一步研究,發(fā)現(xiàn)引起細菌耐藥性升高的原因是由于超廣譜β-內(nèi)酰胺酶(ESBLs)活性的升高引起的,而致病能力的降低可能與生物被膜的減少相關(guān)。 其次,利用轉(zhuǎn)座突變的方法在PAO1全基因組的水平上篩選MuxABC的調(diào)節(jié)基因,共得到15株影響MuxABC的突變體,隨機PCR測序確定了10個抑制子,4個激活子,這些調(diào)節(jié)基因從ClassⅠ至ClassⅣ均有分布,它們不同程度的調(diào)節(jié)了MuxABC的表達。 通過基因互補,變變體構(gòu)建,抗生素敏感性及相關(guān)毒性因子測定,細菌運動性分析等手段對PA2581進行了深入研究,發(fā)現(xiàn)PA2581為MuxABC外排泵抑制子,PA2581的缺失導致MuxABC外排泵表達的增強,從而引起相應的表型變化。其調(diào)節(jié)方式有待進一步研究。 本研究對于深入了解銅綠假單胞菌群體耐藥機制,尋找潛在藥物作用靶點,開發(fā)新型抗菌藥物具有重要意義。
[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，

本文編號：1940917