鲍曼不动杆菌16S rRNA甲基化酶编码基因分布研究

发布时间：2018-05-20 08:20

本文选题：鲍曼不动杆菌 + 16S　；参考：《浙江大学》2007年硕士论文

【摘要】： 不动杆菌是一类不发酵糖的革兰阴性杆菌，广泛分布于水、土壤、医院环境和人体的皮肤表面，已成为医院获得性感染的主要致病菌之一，主要引起医院获得性肺炎尤其是呼吸机相关性肺炎、菌血症、尿路感染、继发性脑膜炎等。随着广谱抗菌药物的广泛使用，，多重耐药不动杆菌日趋增多，极易造成流行，给临床抗感染治疗带来很大的困难，也对院内感染的控制提出了新的要求。氨基糖苷类抗生素是临床上治疗革兰阴性菌所致严重感染的常用药，常与细菌细胞壁活性抗菌药物联合应用。近年来我国鲍曼不动杆菌分离率明显增加，耐药率也不断上升。且已出现对β-内酰胺类、氨基糖苷类、氟喹诺酮类抗菌药物同时耐药的多重耐药菌株的流行。对多重耐药鲍曼不动杆菌中新出现的耐药机制进行研究有利于进一步了解耐药的分子机理，指导临床用药。本研究收集了2004年12月-2005年12月我国6省市8家省级医院、浙江省11个地区17家市级医院临床分离的700株鲍曼不动杆菌；采用琼脂稀释法测定其对5种氨基糖苷类抗生素的MIC值；PCR筛选三种16S rRNA甲基化酶基因armA、rmtA、rmtB，克隆测序明确基因型；脉冲场凝胶电泳(PFGE)分析菌株的同源性；接合试验、质粒抽提，以及Southern杂交确定armA基因定位。结果显示：700株鲍曼不动杆菌对妥布霉素、阿米卡星、庆大霉素、异帕米星、奈替米星耐药率分别为67.7％、70.9％、75.7％、63.5％、71.5％；对5种氨基糖苷类抗生素全部耐药菌株377株，其中334株检出armA基因；未发现rmtA、rmtB基因阳性菌株。armA基因阳性菌株PFGE分型以A、B、C 3型为主。碱裂解法反复抽提未得到质粒，多次接合试验未成功；Southern杂交显示armA基因分别位于克隆A、B、C菌株染色体ApaI酶切片段约220kb、300kb、220kb大小的片段上。以上研究表明16S rRNA甲基化酶基因armA在我国鲍曼不动杆菌中广泛存在。armA基因位于鲍曼不动杆菌的染色体上。
[Abstract]:Acinetobacter is a class of gram-negative bacilli that do not ferment sugar. It is widely distributed in water, soil, hospital environment and the skin surface of human body, and has become one of the main pathogens of nosocomial infection. Hospital-acquired pneumonia, especially ventilator-associated pneumonia, bacteremia, urinary tract infection, secondary meningitis and so on. With the wide use of broad-spectrum antimicrobial agents, Acinetobacter multidrug resistance is increasing day by day, which is easy to cause epidemic, which brings great difficulties to clinical anti-infection treatment, and puts forward new requirements for the control of nosocomial infection. Aminoglycoside antibiotics are commonly used in the treatment of serious infections caused by Gram-negative bacteria, and are often used in combination with active antimicrobial agents of bacterial cell walls. In recent years, the isolation rate and drug resistance of Acinetobacter baumannii have increased. Multidrug resistant strains with simultaneous resistance to 尾-lactams, aminoglycosides and fluoroquinolones have been found. The study of the new mechanism of drug resistance in Acinetobacter baumannii is helpful to further understand the molecular mechanism of drug resistance and to guide clinical drug use. From December 2004 to December 2005, 700 strains of Acinetobacter baumannii were isolated from 8 provincial hospitals in 6 provinces of China and 17 municipal hospitals in 11 regions of Zhejiang Province. Three 16s rRNA methylase genes were screened by Agar dilution assay for five aminoglycoside antibiotics. The genotypes of three 16s rRNA methylase genes were identified by cloning and sequencing. The homology of the strains was analyzed by pulsed field gel electrophoresis (PFGE). And Southern hybridization to determine the location of armA gene. The results showed that the resistance rates of seven hundred strains of Acinetobacter baumannii to tobramycin, amikacin, gentamicin, isopamicin and netilmicin were 67.77.70.90 and 75.55.55%, respectively, and 377 strains were resistant to all 5 aminoglycoside antibiotics, of which 334 had armA gene. There was no PFGE typing of rmtAgna rmtB gene positive strain and armA gene positive strain. The plasmid was repeatedly extracted by alkaline cleavage method. Southern blot analysis showed that the armA gene was located on the ApaI fragment of the cloned strain Abora C with the size of about 220kb ~ 300kb ~ (2 +) ~ 220kb respectively. These results indicate that the 16s rRNA methylase gene armA is widely present in Acinetobacter baumannii in China, and the gene is located on the chromosome of Acinetobacter baumannii (Acinetobacter baumannii).
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R378

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