铜绿假单胞菌对碳青霉烯类药物的耐药机制研究

A study on the mechanism of the Carbapenems-tolerance in Pseudomona aeruginosa

目的探讨铜绿假单胞菌对碳青霉烯类药物的耐药机制。方法收集2008年11月至2009年4月我院临床分离的铜绿假单胞菌31株,根据药敏结果分为碳青霉烯类耐药组(21株)和碳青霉烯类敏感组(10株)。另设1株标准株ATCC 27853,用亚胺培南-EDTA(乙二胺四乙酸)抑制试验检测菌株是否产生金属酶,采用PCR法检测各菌株的外膜孔道蛋白oprD2基因,探讨铜绿假单胞菌对碳青霉烯类抗生素耐药机制。结果21株耐药株有7株产生金属酶;21株耐药株经oprD2基因扩增,15株阴性,6株阳性,10株敏感株全部阳性。统计学检验结果表明,碳青霉烯类耐药组与敏感组oprD2基因阳性率的差异有极显著性(P(0.01)。结论oprD2基因缺失和金属酶是本院铜绿假单胞菌对碳青霉烯类抗生素耐药的重要机制。

Objective To study the mechanism of the Carbapenems-tolerance in Pseudomona aeruginosa （ P. aeruginosa ）. Method Thirty-one strains of P. aerugirtosa isolated from November 2008 to April 2009 in our hospital were analyzed. According to the results of drug sensitivity test, the thirty-one strains ofP. aeruginosa were divided into Car- bapenems-tolerance group （21 strains） and C arbapenems-sensitive group（ 10 strains）. Meanwhile, a standard strain of P. aeruginosa ATCC 27853 was also studied and an imipenem-EDTA inhibition test was conducted to detect metallo-beta-lae- tamases. PCR method was used to detect the oprD2 gene in P. aeruginosa, so as to study the mechanism of the Carbapenems- tolerance in P. aeruginosa. Result 7 of 21 strains of Carbapenems-tolerance P. aeruginosa produced metallo-beta-lactama- ses ; 15 of 21 strains of Carbapenems-tolerance P. aerug/ru^sa were shown to be oprD2 gene negative, while the other 6 were positive. In contrast,all of the 10 strains of the Carbapenems-sensitive P. aeruginosa were found to be oprD2 gene positive, and so was the standard strain ATCC 27853. The restdts of the Chi-square test revealed that the difference between the positive rates of the oprD2 gene in the Carbapenems-toleranee and sensitive P. aerug/nosa was statistically highly significant. Conclusion Loss of the oprD2 gene and metallo-beta-laetamases-produeing ability were the important mechnisms of the Carbapenems-toleranee in P. aeruginosa of our hospital.