The Effect Of Efflux Pumps On Silica Nanoparticles Through Pseudomonas Aeruginosa

PURPOSETo observe whether the effiux pumps in Pseudomonas aeruginosa have the ability to pump silica nanoparticles out the bacterium,which can provide an experimental basis for the use of silica nanoparticles as drug carrier of antibiotics relevant to the infection of P.aeruginosa.METHODFrom January 2007 to June 2007,24 strains of P.aeruginose,which named S1-S24,were isolated from Second Xiangya hospital of Central South University.The antibiotic resistance analysis for 12 strains P. aeruginose are used MIC method.RT-PCR is used to investigate the expression of four efflux pumps which is MexAB-OprM,MexCD-OprJ,MexEF-OprM,MexXY-OprM.The P.aeruginose signed S24 and PA01 were co-cultured with 30μg/ml or 6μg/ml silica nanoparticles,then picked out in different time points to observe the distribution of the silica nanoparticles under electro microscope,at the same time,the P. aeruginose were picked out to compare the colony number of the P. aeruginose with or without the silica nanoparticles after 24h since adding silica nanoparticles. RESULT1,24 strains of P.aeruginose exhibit high resistance to Cephlosporins antibiotics while relatively sensitive to Quinoloins antibiotics and all of them have multidrug resistance.The result of RT-PCR tell us that there were 20 strains have expression of the efflux pumps,but only six strains have more than two effiux pumps.Among the six strains of P.aeruginose,S24 can express four efflux pump genes at the same time,which are MexA,MexC,MexX and MexE.The wild bacterial strain PA01 only expressed MexAB-OprM.2,To compare the colony number of the normal cultural P. aeruginose and that co-cultured with 30μg/ml or 6μg/ml silica nanoparticles by single factor analysis of variance,P＞0.01,so the different among the three groups has no statistic significance.3,The quantity of the silica nanoparticles in P.aeruginose was uninfluenced by the efflux pumps.There is no different for silica nanoparticles in P.aeruginose that has one or four effiux pumps,but there is much nanoparticles in P.AERUGINOSA in the time point of 12h and 24h than other time points.CONCLUSIONThe silica nanoparticles can be took by and persisted in P. aeruginosa without the effect of the efflux pumps,plus its safety and no toxicity,which provide a research potential for the silica nanoparticles as an antibiotics vector.