临床分离的铜绿假单胞菌对头孢菌素类抗生素耐药机制的研究

发布时间：2018-01-23 10:59

本文关键词： 铜绿假单胞菌耐药机制 β-内酰胺酶主动外排作用　出处：《四川大学》2006年硕士论文　论文类型：学位论文

【摘要】：目的：研究临床分离的62株铜绿假单胞菌对β-内酰胺类抗生素的耐药情况，并探讨其对头孢菌素类抗生素的耐药机制。方法：琼脂二倍稀释法测定7种β-内酰胺类抗生素对铜绿假单胞菌的MIC值；水解Nitrocefin法定性初筛β-内酰胺酶；ESBLs的表型确证试验初筛ESBLs；三维试验检测高产AmpC酶；提取基因组DNA和质粒DNA，用聚合酶链反应(PCR)检测β-内酰胺酶的类型；改良三维试验检测酶抑制剂(克拉维酸、舒巴坦、他唑巴坦、苯唑西林、乙二胺四乙酸)对β-内酰胺酶的抑制作用；转化试验检测β-内酰胺酶基因是否具有转移性；测定β-内酰胺酶的活性单位；氰氯苯腙(CCCP)抑制试验和反转录聚合酶链反应(RT-PCR)检测铜绿假单胞菌对头孢菌素类抗生素的主动外排作用。结果：临床分离的62株铜绿假单胞菌对亚胺培南、美洛培南、头孢吡肟、头孢他啶、头孢哌酮、头孢噻肟、头孢曲松的耐药率分别为45.16％、29.03％、27.42％、30.64％、58.06％、58.06％、67.64％。有24株铜绿假单胞菌产β-内酰胺酶，表型确证试验检测出有3株产ESBLs，，三维试验检测出有3株高产AmpC酶。用PCR方法检测出有19株产TEM型ESBLs，其中有1株仅合并产质粒介导的DHA-1型AmpC酶，其中有1株合并产染色体介导的SHV型ESBLs和质粒介导的DHA-1型AmpC酶，无产
[Abstract]:Objective: to study the resistance of 62 strains of Pseudomonas aeruginosa to 尾-lactam antibiotics and to explore the mechanism of resistance to cephalosporins. Methods: the MIC values of 7 尾-lactam antibiotics against Pseudomonas aeruginosa were determined by Agar double dilution method. 尾 -lactamases were identified by hydrolytic Nitrocefin method. The phenotypic confirmatory test of ESBLs was used to screen ESBLs. High yield AmpC enzyme was detected by three dimensional test. Genomic DNA and plasmid DNA were extracted and the type of 尾 -lactamases was detected by polymerase chain reaction (PCR). The inhibition of 尾 -lactamases by enzyme inhibitors (clavulanic acid, sulbactam, tazobactam, oxacillin, ethylenediamine tetraacetic acid) was examined by modified three-dimensional test. The transformation test was used to detect whether the 尾 -lactamase gene was transferable or not. The activity units of 尾 -lactamases were determined. The active efflux of Pseudomonas aeruginosa to cephalosporins was detected by CCCP-inhibition test and reverse transcriptase polymerase chain reaction (RT-PCR). Results: the resistance rates of 62 strains of Pseudomonas aeruginosa to imipenem, meropenem, cefepime, ceftazidime, cefoperazone, cefotaxime and ceftriaxone were 45.16%, respectively. 29.03 there are 24 strains of Pseudomonas aeruginosa producing 尾 -lactamases. Three strains of ESBLs were detected by phenotypic confirmatory test, 3 strains were detected by 3D test, and 19 strains produced TEM type ESBLs by PCR method. Among them, 1 strain only combined with plasmide-mediated DHA-1 type AmpC enzyme, and 1 strain combined with chromosomal mediated SHV type ESBLs and plasmide-mediated DHA-1 type AmpC enzyme.
【学位授予单位】：四川大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R378

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