FIG 6.

Survival of various mutants against polymyxin. Wild-type and various mutants in genes involved in resistance to AMPs (arnB, dltB, dltD, phoS, phoH, arcA, and gmd) were incubated in the presence of 1 μg/ml (dark bars) or 10 μg/ml (gray bars) polymyxin for 1 h. Samples were diluted and plated onto LB agar plates to assess bacterial viability. Survival values are relative to the original inocula. This experiment was repeated three times. The trends found in the three independent experiments were the same, but variations prevented statistical analysis. Results of a representative experiment are shown.