Fig. 4
Effect of imipenem on the blaNDM−1 expression of all three strains. The qRT-PCR was applied to detect the expression of blaNDM−1 of the last generation cells (OD600 reached 1.5-2.0 within 11-13 h) exposed to imipenem with grade increasing (control, 4 µg/mL, 8 µg/mL, and 12 µg/mL), decreasing (12 µg/mL to 8 µg/mL, 8 µg/mL to 4 µg/mL, and 4 µg/mL to 0 µg/mL), and canceling (12 µg/mL to 0 µg/mL, 8 µg/mL to 0 µg/mL, and 4 µg/mL to 0 µg/mL) doses, respectively