FIG 5.

MICs of the antibiotic-resistant colonies that emerged from treatment with SOS inducers in vitro and in vivo. We collected 2 antibiotic-resistant colonies from the rifampin plates or minocycline plates from E22 cells exposed to zidovudine in vitro or in vivo and archived them at −70°C. After passaging in antibiotic-free LB broth, they were retested for rifampin or minocycline resistance using Liofilchem MIC strips. (A) Rifampin MIC scattergram of 16 colonies collected from 8 separate in vitro experiments. (B) Rifampin MIC scattergram of 15 colonies obtained from 7 separate rabbit experiments. The rifampin MIC of the E22 parental strain is 2.5 μg/ml (Table 1). (C) Minocycline MIC scattergram from minocycline-resistant colonies that emerged on LB medium with 12 μg/ml minocycline in vivo. (The minocycline MIC scattergram from in vitro experiments showed results similar to those in panel C and is not shown.)