抗生素压力下铜绿假单胞菌耐药基因动态监测分析

Dynamic monitoring and analysis of resistant gene of Pseudomonas aeruginosa under antibiotic pressure

目的通过动态监测铜绿假单胞菌同源菌株在抗生素压力下各药物及耐药基因变化,了解其耐药特点,给临床治疗提供可靠依据。方法采用分子生物学方法对60株铜绿假单胞菌进行同源性分析;对同源菌株分组进行AmpC酶、OprD2相对表达水平及GyrA、ParC基因突变比对分析,制备进化关系。结果通过监测发现在抗生素压力下5组同源菌株中4组AmpC酶相对表达水平呈上升趋势(P<0.05),且引起头孢他啶耐药或中介;对于OprD2相对表达水平5组同源菌株均呈下降趋势(P<0.05),其中有3组OprD2表达缺失,导致碳青霉烯类抗生素出现耐药;对于GyrA、ParC基因突变比对分析,存在众多单点突变,并未发现有氨基酸改变。结论铜绿假单胞菌在抗生素压力下容易获得耐药,其中AmpC酶高表达和OprD2表达减弱是导致其对头孢菌素类、碳青霉烯类抗生素耐药的主要原因。

Objective This paper aims to dynamically monitor the drug resistance and the resistant gene changes of Pseudomonas aeruginosa homologous strains under antibiotic pressure,understand their drug resistance characteristics,and provide reliable basis for clinical treatment.Methods Sixty cases of Pseudomonas aeruginosa underwent homological analysis in molecular biological method.The relative expression of AmpC enzyme and OprD2 and the mutations of GyrA and ParC genes were conducted for comparison analysis in the homologous group,so as to prepare the evolutionary relationship.Results Under the pressure of antibiotics,the relative expression of AmpC enzyme in 4 of the 5 homologous groups showed a significant upward trend(P<0.05)and caused ceftazidime resistance or mediation.The relative expression of OprD2 in 5 homologous groups showed a downward trend(P<0.05),of which 3 groups lost the expression of OprD2,leading to the resistance of carbapenem antibiotics.For the comparative analysis of GyrA and ParC gene mutations,there were many single point mutations,and no amino acid changes was observed.Conclusion Pseudomonas aeruginosa is easy to acquire drug resistance under the pressure of antibiotics,and the high expression of AmpC enzyme and the weak expression of OprD2 are the main reasons for its resistance to cephalosporins and carbapenems.