Effect of andrographolide on the mRNA expression of MexAB-OprM efflux pump of Pseudomonas aeruginosa PAOI strain / 中华传染病杂志

ABSTRACT

Objective To develop a real-time polymerase chain reaction(PCR)system to determine transcriptional level of MexAB-OprM multidrug efflux pump gene and to investigate the impact of androgra- pholide on MexAB-OprM gene transcription in Pseudomonas aeruginosa.Methods The fragments of mexB gene of mexAB-oprM operon and 30S rRNA gene rpsL were amplified and cloned into two plas- mids respectively.These plasmids were used as external standards for real-time PCR.Real-time PCR was applied to measure the mRNA transcripition of mexB and rpsL gene in Pseudomonas aeruginosa growing in medium with different concentrations of andrographolide.Results The plasmids for standard curve were constructed successfully.The relative mexB mRNA expressions in 50,100,150 and 200?g/mL andrographolide were 0.04?0.03,0.06?0.07,0.09?0.03 and 0.04?0.03 respectively, which were significantly lower than that in the control(0.24?0.04,P0.05).Conclusion Andrographolide can reduce the transcriptional level of MexAB-OprM,which may he one mechanism for its anti-infection effect.