Detection Of Acra/Acrb And The Relationship Of Acra/Acrb And Energy Inhibitor CCCP In Multidrug Resistance Escherichia Coli

Objective:To investigate the resistant situation of local Escherichia, detect efflux pump gene acra/acrb in Escherichia coli,and research on the influence of MIC which CCCP associate wtih two fluoroquinolones.Method:1.Disk diffusion test:The susceptibility of 71 strains of E.coli to 6 antibiotics were detected by disk diffusion which was recommended by NCCLS.The 6 antibiotics were(CTX),aztreonam (ATM), Gentamicin (G), streptomycin(S),cefotaxime ciprofloxacin (CIP),levofloxacin (LEV), Escherichia coli ATCC 25922 was used for control strain.2.PCR:The gene of acra/acrb were determined by PCR. According to squences of acra/acrb,2 pairs of primers were designed.The template of PCR reaction was bacteria genomic DNA,which was extracted by biospin bacteria genomic DNA extraction kit. PCR products were visualized on horizontal agarose gels with ethidium bromide after electrophoresis and were sent to detect the gene sequences.3. Constant broth dilution method:10 Multidrug resistance strains and 5 sensitive strains were selected, minimum inhibitory concentration (MIC)to ciprofloxacin and levofloxacin of Escherichia coli were tested.4.Influence of MIC which CCCP association wtih two fluoroquinolones:10mmol/L 15ul CCCP was added in the test tubes,in which two drugs were diluted, then bacteria liquor lml was added, the final concentration of CCCP came to 75umol/L.The tubes had been incubated for 18 hours at 37℃,the change of MIC were compared.Results:1.The resistant rates of Escherichia coli to gentamicin(G),streptomycin(S),cefotaxime(CTX),aztreonam(ATM),ciprofloxac in(CIP),levofloxacin(LEV) was 60.20%,40.85%,59.15%,30.99%,73.24%, 60.38%, respectively. The average/cross resistance rate toβlactans was 35.92/25.35%,aminoglycosides 50.41/39.44%.fluoroquinolones 68.32/60.56%. Multidrug resistance was the main part of resistant patterns(51.11%).2. Acra/acrb positive rate of multi-drug resistant strains was 89.00/80.08%,double resistant strains 43.37/43.37%,simple resistant strains 55.56/44.44%,sensitive strains 50.00/33.37%.Acra/acrb positive rate had statistical significance by chisquare test. Acra/acrb positive rate of resistant strains to CTX was 69.05/64.28%,ATM 50.00/50.00%,G 68.05/57.45%,S 44.83/51.72%,,CIP 82.69/80.77%,LEV 75.56/71.77%.Acra/acrb positive rates had statistical difference by chisquare test.The resistant strains to CIP/LEV compared with other strains had statistical difference.3.The MIC of multidrug resistant Escherichia coli had different changes,the sensitive strains had no change;the variation of MIC in resistant and sensitive strains had statistical difference.Conclusion:1.The resistance to 6 antibiotic of local E.coli is common, and multidrug and cross resistance is obivous.2.Acra and acrb are important reason of multidrug reasistance, and also have relationship with resistant fluoroquinolone of E.coli.3.Efflux system inhibitors CCCP combine with fluoroquinolone antibiotics will reduce MIC.