FIG. 1.

Cellular accumulation of CIP. [¹⁴C]CIP accumulation by FQ-resistant mutants derived in vitro from E. coli K-12 strain AG100 and its Mar mutant AG112 was assayed at 30°C at equilibrium after addition of 10 μM CIP, as described in Materials and Methods. Cells carried either the wild-type acrAB gene (solid bars) or had an acrAB deletion (hashed bars). ODU₆₀₀, OD₆₀₀ units.