摘要
目的:探讨临床分离的铜绿假单胞菌的主动外排系统MexAB-OprM与其对碳青霉烯类药物耐药之间的关系,研究其耐药分子机理。方法:测定临床分离的铜绿假单胞菌对亚胺培南和美罗培南的体外抗菌活性,根据耐药情况,分为碳青霉烯类药物敏感组和碳青霉烯类药物耐药组;应用RT-PCR方法,研究两组菌株的主动外排系统MexAB-OprM中结构基因oprM的mRNA表达水平;用PCR法扩增两组菌株的泵调节基因mexR,对扩增产物进行DNA双向测序。结果:耐药组oprM的mRNA表达水平明显高于敏感组(P<0.05);一株菌发现MexR第126位氨基酸突变(缬氨酸→谷氨酸),两株菌发现MexR第70位氨基酸突变(精氨酸→谷氨酰胺)。结论:山西医科大学第一医院临床分离铜绿假单胞菌的主动外排系统MexAB-OprM参与碳青霉烯类药物的耐药;MexAB-OprM高表达的分子机理可能与泵调节基因mexR的突变以及其他突变型有关。
Objective：To probe the relationship between active efflux pump MexAB-OprM in clinical isolated Pseudomonas aeruginosa strains and the carbopenem resistance,and study its molecular mechanism of drug resistance.Methods：Antimicrobial susceptibili of Pseudomonas aeruginosa clinical isolates were tested by Kirby-Bauer method against inipenem and meropenem.The strains were divided into Carbapenems-resistant group and Carbapenems-sensitive group according to carbopenems sensitivity.RT-PCR method was used to study the level of mRNA expression of oprM which was the structural gene in active efflux pump MexAB-OprM.PCR method was used to amplify the mexR gene of these two group strains,and analyze the PCR products with DNA sequencing.Results：The expression level of mRNA of oprM in the strains of the Carbapenems-resistant group was significantly higher than those in Carbapenems-sensitive group（P0.05）.One strains had the amino acid substitu-tionin in MexR protein,Val（GTG）→Glu（GAG） at the position of amino acid 126.Two strains had the amino acid substitutionin of Arg（CGG）→Gln（CAG） at the position of amino acid 70.Conclusion：In The First Affiliated Hospital of Shanxi Medical University,active efflux pumps in clinical isolated Pseudomonas aeruginosa mediate the resistance to carbopenem.High level expression of MexAB-OprM is related to mexR gene mutation and other mutant type.
出处
《中国卫生检验杂志》
CAS
2010年第2期243-245,共3页
Chinese Journal of Health Laboratory Technology
