Investigation On The Change Of Resistance Of Pseudomonas Aeruginosa And The Effect Of Quorum Sensing System On Expression Of Virulence Factors

Pseudomonas aeruginosa is a common clinical non-fermenting pathogenicbacterium, which played a very important role in hospital infections, such asventilating respiratory infections, cystic fibrosis patients with secondary pneumoniaand the secondary burning infections. In recent years, with the use of antibiotics(especially non-standard use of antimicrobial drugs and abuse) the resistance rate ofP. aeruginosa showed a gradual upward trend.The mechanisms of PA resistance were complex, virulence factors that includethe expression of elastase, pyocyanine, swimming ability are the important causes ofPA resistance. Studies have shown that between bacterial quorum sensing systemitself (ie QS system) and the expression of virulence factors have a certainrelationship.The issue analyzed the correlation between the use of antibacterial drugs withPseudomonas aeruginosa resistance level changes in2005-2012; investigated thechanges of resistance of Pseudomonas aeruginosa after specific rectifications ofantibiotics in a hospital; studied the effect of Pseudomonas aeruginosa QS system onvirulence factor activity.1、 Analyze the correlation between the use of antibacterial drugs withPseudomonas aeruginosa resistance level changes in2005-2012Objective：To study the correlation between the use of antibacterial drugs withPseudomonas aeruginosa resistance level changes in2005-2012.Methods：The applications of antibiotics in the hospital from2005to2012wereevaluated by calculating DDDs．The correlation between the use of antimicrobialagents and bacterial resistance was analyzed by SPSS16.0statistical software. Results： Amikacin, cefepime, ceftazidime, and levofloxacin DDDs withPseudomonas aeruginosa respective resistance rates between high positivecorrelation, but not statistically significant (P>0.05).Positive correlation between theuse of cephalosporins and imipenem resistance rates between correlation wasstatistically significant (P<0.05). The use of composite preparation and amikacin,meropenem resistance rates are positively correlated, the correlation was statisticallysignificant (P <0.05). There is a positive correlation between the use of quinoloneantibiotics meropenem resistance rates, the correlation was statistically significant (P<0.05). The carbapenem antibiotics use of meropenem and imipenem resistance ratesare positively correlated, the correlation was statistically significant (P <0.05).2、 Analysis of the resistance of Pseudomonas aeruginosa after specificrectifications of antibiotics in a hospitalObjective：To investigate the changes of resistance of Pseudomonas aeruginosaafter specific rectifications of antibiotics in a hospitalMethods：The data that resistance rates of Pseudomonas aeruginosa was collectedand organized for12quarters by WHONET-5.4. The period was divided from2010to2012by2011.07. The characteristics of drug resistance were statistically analyzedin the hospital from2010to2012after specific rectifications of antibiotics bySPSS16.0.Results：Pseudomonas aeruginosa resistance rates are lower than before therenovation, this resistance rate of20antibiotics after remediation on nitrofurantoin,ciprofloxacin, meropenem, minocycline, piperacillin, piperazinepiperacillin/tazobactam, cefepime, cefoperazone, cefoperazone/sulbactam,ceftriaxone, cefotaxime, ceftazidime, tobramycin, levofloxacin resistance rates wasstatistically significant (P <0.05).3、Study on the effect of Pseudomonas aeruginosa QS system on virulence factoractivity. Strain Source:40Pseudomonas aeruginosa were collected from June2012toJune2013in the a hospital. All strains were identified by VITEK-2system.Methods：The resistance of isolates was determined by the agar doublingdilution method. The elastase activity was detected by the enzymolysis and stainingmethod; the pyocyanine vitality was determined by the two phase extraction; theswimming ability was measured by cultivation and measurement. The result of testswas analyzed by SPSS16.0.Results：The comparison between the QS system failure and the normal group on elastaseactivity and the pyocyanine vitality had significant difference (P<0.05). The contrast analysis onthe swimming ability was not statistically significant.Conclusion:1、Frequency of use of antimicrobial agents (ie DDDs) to some extent willaffect the bacterial drug resistance; the correlations was showed between the usageof different types of antimicrobial and bacteria resistance rates to certainantimicrobial drugs. Use of antibiotics can cause Pseudomonas aeruginosaantimicrobial resistance rates raise.2、 In recent years, the resistance rates of Pseudomonas aeruginosa toantimicrobia has a downward trend, the resistance rates have decreased significantlyparticularly in2011and2012. Rational use of antimicrobial drugs helps to reducethe resistance rate of bacterial to antimicrobial drugs. The effect on antimicrobialrectification is remarkable in the hospital.3、The impact of QS system to elastase activity and pyocyanine activity wasstatistically significant. Further study will be needed that the impact to theswimming ability.