FIG. 1.

Reserpine-mediated inhibition of ciprofloxacin efflux and growth in ciprofloxacin of S. aureus strain SA-1199B. (A) Ciprofloxacin accumulation as measured by a fluorometric method (at 10 μg of ciprofloxacin per ml), both with and without reserpine; (B) mid-log-phase OD values for growth of SA-1199B in various ciprofloxacin concentrations, with and without reserpine; (C) growth inhibition assays for SA-1199B at one-fourth the MIC of ciprofloxacin, with and without reserpine. Symbols: closed circles, experiments done with drug alone; open circles, experiments done with drug and reserpine; vertical bars, range of results obtained for the duplicate experiments.