Study On The Correlation Between The Imipenem-resistant Pseudomonas Aeruginosa And The Class Ⅰ Integron In Drug Resistance

Objective Through serial anglysis of the characteristics of antimicrobial resistance and the related gene of mtallo-β-lactamase of the imipenen-resistant Pseudomonas aeruginosa(IMPRPa).To disuss the impact of bacterium carrying mtallo-β-lactamase gene and correlation between the classâ… integron and drug-resistant of Pseudomonas aeruginosa.Methods MIC tests were performed to detect the antibiotic resistance status in clinic IMPRPa isolates that had been idengtified by Vitek-2.Compound paper disk diffusion was adopted to screen mtallo-β-lactamase-producing IMPRPa strains; The correlated genes of classâ… integrase gene(intâ… ) and mtallo-β-lactamase(such as VIM-2 and IMP-1) were detected by PCR method and confirmed by sequencing.Results 1.The antibiotic resistance characteristics of 81 IMPRPa strains to 12 clinical commonly used antimicrobial agents show as below:100%resistant to tetracycline(TE),＞80%resistant to ciprofloxacin(CIP),meropenerm(MEM),gentamicin(GN),piperacilin(PIP),Resistaance ratios of Pseudomonas aeruginosa to levofloxacin(LEV),cefepime(FEP),amikacin(AMK),aztreonam(ATM) were77.8%,50.6%,38.3%,35.8%,＜30%resistant to ceftazidime(CAZ),piperacilin/TAZ(TZP),cefopcrazone/sulbactam(SCF).Compare the resistance analysisthe of IMPRPa with the non-IMPRPa,CIP,ATM,MEM,GN,EFP,LEV,PIP,TZP have significance difference(P＜0.05).2.The positive ratio of classâ… integrase was 69.4%.In IMPRPa the gene was detected 85.2%.Among the non-IMPRPa strains,the positive ratio of intâ… was 27.7%.The DNA sequencing of PCR products were consistent with it in the Genbank(99%).Resistance ratio of intâ… positive IMPRPa strains were higher than that of intâ… negative IMPRPa strains(P＜0.05).The producing of intâ… gene is the important mechanism that cause Pseudomonas aeruginosa drug resistant to IMP and intâ… is closely correlated to IMPRPa multidrug-resistance.(P=0.000,r= 0.491).3.Using substrate ceftazidime and imipenem(IMP),enzyme inhibitor EDTA·Na₂,the microbe sensitivity synergic tests were processed by KB method in MH agar.18.5%(15/81) were mtallo-β-lactamase-producing strains.The VIM-2 gene of mtallo-β-lactamase has been detected by PCR method,but not detected the IMP gene.Compare the resistance ratio of blaVIM positive strains with the blaVIM negative strains have non-significance difference(P＞0.05)Conclusion The drug resistance to commonly used antibiotic of IMPRPa was very strong and their multidrug-resistance phenomenon is terribly serious,intâ… is closely correlated to IMPRPa multidrug-resistance.The VIM-2 gene is major type of the mtallo-β-lactamase in Kunming,but the resistant ratio of mtallo-β-lactamase positive strains and mtallo-β-lactamase negative strains had no-significant difference;explained that produce mtallo-β-lactamase is not the main mecharism of cause Pseudomonas aeruginosa drug resistant to carbapenems.