铜绿假单胞菌MexAB-OprM型主动外排系统与多重耐药性的研究

发布时间：2018-04-22 19:00

本文选题：铜绿假单胞菌 + 主动外排系统　；参考：《福建医科大学》2010年硕士论文

【摘要】： 目的：了解本地区临床分离铜绿假单胞菌MexAB-OprM型外排系统和膜孔蛋白OprD2的表达情况及其与铜绿假单胞菌多重耐药的关系,为临床抗感染治疗及医院感染的监测和控制提供循证医学依据。方法： 2008年7月至2009年6月我院住院患者送检标本分离铜绿假单胞菌381株(同一患者同类标本分离菌株不重复计入)。采用VITEK 2 Compact自动微生物分析仪进行细菌鉴定和药敏测定。选取多重耐药(对三类或以上抗生素耐药)的铜绿假单胞菌,分别以微量肉汤稀释试验检测MexAB-OprM型主动外排系统、荧光定量PCR技术对该型外排系统及OprD2进行相对定量测定,对高表达MexAB菌株的调节基因mexR进行PCR扩增,并对产物进行测序。结果： 1.铜绿假单胞菌的感染以儿童和老年人居首,在全院各科室中,ICU患者铜绿假单胞菌分离率最高(14.2%),从感染部位上,主要分布于呼吸道(62.2%)。 2.铜绿假单胞菌的耐药情况相当严峻,对多数常用抗生素均有较高的耐药性,但哌拉西林／他唑巴坦、丁胺卡那霉素等抗生素目前仍是治疗铜绿假单胞感染的有效抗菌药物。 3.质子泵抑制剂CCCP对环丙沙星的抗菌效果影响较大,有15株铜绿假单胞菌的MIC下降8倍以上,其中6株的CAZ在CCCP存在的情况下MIC也下降8倍以上,另有两株仅有头孢他啶的MIC下降8倍以上。亚胺培南的抗菌活性基本不受CCCP的影响。 4.对头孢他啶耐药和敏感的两组铜绿假单胞菌MexAB-OprM型主动外排系统表达量有统计学差异(P0.05),对环丙沙星耐药和敏感的两组铜绿假单胞菌MexAB-OprM型主动外排系统表达量有统计学差异(P0.05),但对亚胺培南耐药和敏感的两组,该型外排系统的表达量无差别(P0.05)。 5. mRNA相对定量与头孢他啶的CCCP抑制试验结果的一致性较好,环丙沙星抑制试验阳性菌株中有7株相对定量不高。 6.膜孔蛋白OprD2基因mRNA的定量检测结果显示,亚胺培南耐药组的表达量低于敏感组,并且两者差异有统计学意义(P0.05) 结论： 1.铜绿假单胞菌是医院感染重要病原菌,显示多重耐药,应该合理选择抗生素。 2.铜绿假单胞菌MexAB-OprM型主动外排系统的高表达是其存在多重耐药的重要机制。 3. MexAB-OprM型主动外排系统的高表达与铜绿假单胞菌对CIP和CAZ的耐药有关,而非IMP的耐药机制。 4. OprD2的表达减少是铜绿假单胞菌对IMP出现耐药的重要机制。
[Abstract]:Objective: To investigate the expression of MexAB-OprM type efflux system and membrane-porin OprD2 in clinical isolates of Pseudomonas aeruginosa and its relationship with multidrug resistance of Pseudomonas aeruginosa, and to provide evidence based medicine basis for clinical anti-infection therapy and monitoring and control of nosocomial infection. Methods: From July 2008 to June 2009 381 strains of Pseudomonas aeruginosa were isolated from inpatients in our hospital. VITEK 2 Compact automatic microbiological analyzer was used to identify bacteria and determine drug sensitivity. Pseudomonas aeruginosa with multidrug resistance (resistance to three or more antibiotics) was selected to detect the active efflux system of MexAB-OprM type by dilution test of micro broth, and the efflux system and OprD2 were detected by fluorescence quantitative PCR technique. The regulatory gene mexR of high expression MexAB strain was amplified by PCR and the product was sequenced. Results: 1. The most common infection of Pseudomonas aeruginosa was in children and the elderly. The isolation rate of Pseudomonas aeruginosa was the highest in ICU patients in the whole hospital. 2. The drug resistance of Pseudomonas aeruginosa is very severe and has high resistance to most commonly used antibiotics. However, piperacillin / tazobactam and amikacin are still effective antimicrobial agents in the treatment of pseudomonas aeruginosa infection. 3. Proton pump inhibitor CCCP had a great effect on ciprofloxacin. The MIC of 15 strains of Pseudomonas aeruginosa decreased more than 8 times, and the CAZ of 6 strains decreased more than 8 times in the presence of CCCP. In the other two strains, the MIC of only ceftazidime decreased more than 8 times. The antibacterial activity of imipenem was not affected by CCCP. 4. The expression of ceftazidime resistant and sensitive MexAB-OprM active efflux system of Pseudomonas aeruginosa was significantly different (P 0.05), and the expression of MexAB-OprM active efflux system of ciprofloxacin resistance and sensitive two groups of Pseudomonas aeruginosa was statistically significant. P0.05, but resistant to imipenem and sensitive to imipenem, There was no difference in the expression of P0.05 in this type of efflux system. 5. The relative quantitative analysis of mRNA was in good agreement with the results of ceftazidime CCCP inhibition test. 6. The quantitative detection of mRNA of membrane pore protein OprD2 gene showed that the expression of imipenem resistant group was lower than that of sensitive group, and the difference was statistically significant (P0.05). Conclusion: 1. Pseudomonas aeruginosa is an important pathogen of nosocomial infection. 2. The high expression of MexAB-OprM active efflux system in Pseudomonas aeruginosa is an important mechanism of multidrug resistance in Pseudomonas aeruginosa. 3. The high expression of MexAB-OprM type active efflux system was related to the resistance of Pseudomonas aeruginosa to CIP and CAZ, but not to the mechanism of IMP resistance. 4. The decrease of OprD2 expression is an important mechanism of resistance of Pseudomonas aeruginosa to IMP.
【学位授予单位】：福建医科大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R378.991

【参考文献】