Aureus Silicon Quinolone Resistance, Active Efflux Mechanism

Objects: Unsertake the initial research of the effection,characteristic,and control method of the active efflux mechanism in straphylococcus aureus(S.a) resistant to quinolones and inverstigate the prevalence of resistantance by active efflux in clinic isolates.Meterials and methods: Straphylococcus aureus standary strain ATCC25923 and clinic isolates susceptible to quinolone were inoculated onto MH agar containing ofloxacin at a concentration of 4 x the MIC(in the presence or absence of 20 ~t g of reserpine/ml),following incubation at 350 for 48h,observe the inhibiting effection of reserpine to the occurence of induced resistance and determine the MIC of the induced resistant strain to ethidium bromide(EB),ofloxacin and ciprofloxacin(in the prevence or absence of 20 i-t g of reserpine/ml),observe the influrence of reserpine to the MIC of induced resistant strains.And use the fearture of EB which fluorescence was strengthened when combined with DNA.Observe the accumulation and loss of EB.Use reserpine inhibiton test to survey the prevalence of active efflux in clinic S.a resistant to quinolone.results: Reserpine can inhibite the rate of resistance to quinolone in S.a, and can decrease the MIC of induced resistant strains.Reserpine can inhibit the active efflux of EB from the cytoplasm of S.a. Reserpine inhibition test is a simple and direct method. 50% stains of clinic isolates resistance to quinolone by active efflux mechinism. Conclusion:active efflux is a important mechnism in S.a resistant to quinolone.Reserpine can inhibit the rate of induced resistant S.a by quinolone ,and decrease the MIC of resistant strains.so reserpine and quinlone have cooperativity ,authough the reserpine can抰 used in clinic, but would previde the theory basis to explore the similar drug.