Mutation rates to ciprofloxacin resistancea.

aMutation rates (µ) per replication and 95% confidence limits (CL) were calculated as described in Material and Methods. Mutation rates for the WT and mutator (mutS, mutT, mutY and mutM) strains were calculated at 1.0 µg/ml Cip. Assays with 2-aminopurine (2AP), cisplatin (CPT) and hydrogen peroxide (HP) were performed at 0.5 µg/ml Cip. bMutation rates calculated for the WT strain at each set of experiment (mutator strain and mutagen assessment) were used for data normalization.