AdeABC主动外排系统与鲍曼不动杆菌多重耐药性的研究

发布时间：2018-06-29 10:24

本文选题：鲍曼不动杆菌 + 多重耐药　；参考：《中国医科大学》2009年硕士论文

【摘要】： 研究背景鲍曼不动杆菌是引起院内感染的重要病原菌,易引起医院获得性肺炎、菌血症、泌尿系统感染、脑膜炎、软组织感染以及腹腔内感染等严重感染。特别是近年国内外报道多重耐药鲍曼不动杆菌在重症监护病房、血液病房引起暴发流行,病死率极高。随着鲍曼不动杆菌感染治疗越来越困难常表现为对多种抗菌药物耐药即多重耐药,临床治疗也面临着严峻的挑战。因此加强对其多重耐药机制的研究,有助于临床医生选择合适抗菌药物,同时对控制鲍曼不动杆菌引起的院内感染也具有重要的现实意义。目的目前大多数不动杆菌为多重耐药(Multi-drug Resistant Acinetobacter,MDR-A),即同时对β-内酰胺类、喹诺酮类、氨基糖苷类耐药。近年来相关研究表明主动外排机制是引起多重耐药的重要因素,而我国此类研究不多。本文就本院鲍曼不动杆菌耐药性进行分析,通过外排表型试验了解主动外排机制在介导鲍曼不动杆菌多重耐药机制中的作用;同时进行外排泵相关基因检测;上述研究将为明确本地区鲍曼不动杆菌多重耐药机制提供有益线索。方法回顾性分析我院7年来鲍曼不动杆菌对10种临床常用抗菌药物的耐药监测结果;筛选2007年1月-2007年12月中国医科大学附属一院临床分离的鲍曼不动杆菌,经Vitek2系统进一步鉴定确定为鲍曼不动杆菌;采用Kirby-Bauer纸片扩散法检测鲍曼不动杆菌对12种抗菌药物的敏感性筛选出50株多重耐药菌;采用琼脂稀释法测定亚胺培南,头孢噻肟,环丙沙星以及阿米卡星的MIC值,同时进行外排表型试验;采用PCR方法扩增外排泵编码基因及调节基因,通过DNA序列测定以及与GenBank序列的比对分析,了解外排泵的基因结构。结果 50株多重耐药菌株对亚胺培南、头孢噻肟、环丙沙星和阿米卡星的MIC值的范围分别为1-128μg/ml,128-512μg/ml,16-128μg/ml和32-1024μg/ml。同时以亚胺培南、头孢噻肟、环丙沙星和阿米卡星作为底物,四种抗菌药物外排表型检测结果显示:在25μg/ml利血平存在条件下,50株多重耐药菌分别有46、50、49和50株菌MIC值降低4倍或4倍以上,呈现明显的外排作用;而在CCCP存在条件下,分别有21、44、26和48株菌MIC值降低4倍或4倍以上。两种外排泵抑制剂之间存在不同的外排效果。外排泵相关基因检测结果:泵编码基因adeB的检出率为94%,而双组份调节系统adeR、adeS基因的检出率分别为96%、92%。讨论我院鲍曼不动杆菌对β-内酰胺类、磺胺类及氨基糖苷类药物的敏感性呈逐年下降趋势。研究发现外排泵抑制剂利血平和CCCP能明显提高多重耐药鲍曼不动杆菌药物的体外抗菌活性。这提示本研究所收集的鲍曼不动杆菌的多重耐药性与主动外排机制密切相关,同时两种外排泵抑制剂的不同外排效果提示可能存在除AdeABC型以外的泵出系统。本研究将为监测本地区鲍曼不动杆菌的多重耐药机制奠定基础。
[Abstract]:Background of the study

It is an important pathogen causing nosocomial infection , which is apt to cause severe infections such as pneumonia , bacteraemia , urinary system infection , meningitis , soft tissue infection and intra - abdominal infection .

Purpose

In recent years , the study shows that the active efflux mechanism is one of the most important factors causing multiple drug resistance .

method

A retrospective analysis was made on the results of resistance to antibiotics in ten clinical commonly used antibiotics in our hospital from January 2007 to December 2007 . The results were as follows : 50 strains of multiple drug resistant strains were screened for susceptibility to 12 antibacterial drugs from January 2007 to December 2007 . The gene and regulatory genes were amplified by agar dilution method . The gene structure of efflux pump was determined by DNA sequencing and comparison with GenBank .

Results

In the presence of 25 渭g / ml reserpine , there were 46 , 50 , 49 and 50 bacterial MIC values of 46 , 50 , 49 and 50 strains decreased by 4 or more than 4 times or more respectively . The results showed that the detection rate of the two efflux pump inhibitors was 94 % and the detection rate of adeR and adeS genes was 96 % and 92 % respectively .

discuss

The sensitivity of acinetobacter baumandii to 尾 - lactam , sulfanilamide and aminoglycosides has been decreasing year by year . It is found that both reserpine and CCCP of efflux pump can significantly increase the antibacterial activity in vitro . This suggests that the multiple drug resistance of baumanii collected by this study is closely related to the active efflux mechanism , and the different efflux effect of two efflux pump inhibitors suggests that there may be pumping systems other than AdeABC type . This study will provide the basis for monitoring the multiple drug resistance mechanism of baumanii in the region .
【学位授予单位】：中国医科大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R378.9

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