Figure 1.

Reactive species of oxygen (ROS) experiment by fluorimetry. (A) ROS production for five E. coli isolates carrying distinct plasmids after treated with sub-inhibitory concentration of zinc oxide (ZnO); (B) ROS production for the E. coli isolates carrying distinct plasmids after treated with sub inhibitory concentration of copper sulphate (CuSO₄). IF/OD, intensity of fluorescence/optical density; CTRL, control (no treated); ZnO (IncL and IncI1, 512 µg/mL; IncA/C, IncF, and IncX3, 128 µg/mL); CuSO₄ (all plasmids, 512 µg/mL). Data are presented in means and standard deviations. *, p < 0.05 (*, against the respective control); **, p ≤ 0.01; ***, p ≤ 0.001; ****, p ≤ 0.0001.