The effect of small interfering RNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps in vivo
Objective To identify the efficacy small interfering RNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps.Methods Four siRNA ( siRNA1,siRNA2,siRNA3 and siRNA4) against mexB gene were designed and prepared by electricity transference in vitro.MICs of antibiotic combined with efflux pump inhibitors against multiple resistant strain PAO1 and PAO3 were determined by E-test method.The mRNA expression levels of efflux pump gene (mexB) were quantified by real time fluorescent quantitative PCR.Results siRNA expression vectors were constructed success by enzyme cut method.48 after PAO1 and multiple drug resistant PAO3 transfected with siRNA4,the sensibilities to antibiotic were enhanced.48 after PAO1 and multiple drug resistant PAO3 transfected with siRNAl,siRNA2 and siRNA3,the sensibilities to antibiotic didn't change obviously.48 after PAO1 and multiple drug resistant PAO3 ttransfected with siRNA4,the expression level of mexB was decreased obviously (P ＜ 0.05 ).48 after PAO1 and multiple drug resistant PAO3 transfected with siRNA1,siRNA2 and siRNA3,the expression level of mexB didn't change obviously.Conclusion siRNA against Pseudomonas aeruginosa expressing MexA-MexB-OprM efflux pumps enhanced the sensibility to antibiotic and inhibited the expression of mexB gene.Our results demonstrate the using RNAi may be potential targets for novel therapies directed against treatment of antibiotic-resistant infections. 
 
Key words: 
Small interfering RNA;  Pseudomonas aeruginosa;  MexA-MexB-OprM efflux pumps