TABLE 2.

Overview of the MFs, mutation rates, and levels of resistance of the GO mutants

MutantDoubling time (min)Mutation rateMean MF in response to:MIC (mg/liter) by Etesta (size of resistant mutant subpopulationb)
Rifampin (300 μg/ml)Streptomycin (500 μg/ml)PIPCAZTOBCIPATM
PAO126 ± 0.66.75E-091.81E-88.48E-102 (+)21.50.191.5
PAO1/pUCP261.37E-85.38E-10
PAO1ΔmutY::Gm25.7 ± 1.73.85E-081.36E-73.51E-92 (++)1.5 (++)1.5 (+)0.19 (+)1 (+)
PAO1ΔmutY::Gm/pLM1006.36E-81.29E-9
PAO1ΔmutT::Gm27.7 ± 1.81.28E-075.07E-71.18E-72 (+++)2 (+++)1.5 (++)0.25 (++)1.5 (++)
PAO1ΔmutT::Gm/pLM1013.91E-81.69E-9
PAO1ΔmutM::Gm27.3 ± 16.38E-092.78E-81.69E-92 (++)1.5 (+)1.50.191.5
PAO1ΔmutM::Gm/pLM1022.53E-83.72E-10
  • a PIP, piperacillin; CAZ, ceftazidime; TOB, tobramycin; CIP, ciprofloxacin; ATM, aztreonam.

  • b The numbers of resistant mutant colonies in the inhibition zone are as follows: +, <10; ++, 10 to 100; +++, >100 (35).