Effects of efflux pump proteins in inner membrane of gonococci on ciprofloxacin resistance level

  Objective   Tofind the relationship betw een effluxpump proteins in the inner membrane and gonoco cci resis tance to ciprofloxacin.

  Methods   NaN₃ was used as an inhibitor to effluxpump proteins, and the quantity of ciprofloxacin up take and accumulation in gonococci were determined under twokinds of situation, with NaN₃ and without NaN₃, respectively.

  Results   The quantity of ciprofloxacin uptake in gonococci was limited, and the limitation of ciprofloxacin-susceptible and ciprofloxacin-resistant gonococci were 70-110ng and 20-55ng, respectively.Without NaN₃, the quantity of ciprofloxacin accumulation in ciprofloxacin-suscept ible gonococci was 94.2ng, which was sig nificiently more than 39.4ng in ciprofloxacin-resistant g onococci(P < 0.01);After NaN₃ was added, the former was 95ng, nodifferent from that without NaN₃(P > 0.05), but the latter increased to 78ng, obviously more than that without NaN₃(P < 0.05), and it was no different from that in ciprofloxacin-susceptible gonococci without NaN₃(P > 0.05).There were no effluxpump proteins in the inner membrane among 6 strains ciprofloxacin-susceptible gonococci and among 2 strains lo wlevel ciprofloxacin-resistant gonococci.Effluxpump proteins exsited in the inner membrane among 4 strains high level ciprofloxacin-resistant gonococci.

  Conclusion   The effluxpump could actively tranfer ciprofloxacin out of gonococci cytoplasm, the quantity of ciprofloxacin accumulation in cytoplasm reduced, which was an impor tant factorof gonococci high level resistance to ciprofloxacin.NaN₃ could inhibit those function of effluxpump.