FIG. 6.

Analysis of RN6390 and KB350 after exposure to penicillin with the Live/Dead BacLight bacterial viability kit (Molecular Probes, Inc.). Exponentially growing RN6390 and KB350 cells were treated with 20× MIC of penicillin (A and C, respectively) or left untreated (B and D, respectively). Samples of each culture were collected 2 h after the addition of penicillin and were prepared and analyzed as described in Materials and Methods. The population of dead or damaged cells in each panel is represented by a decrease in green fluorescence (FL1).