Figure 11.

(A) AEA increases the intracellular level of norfloxacin. MDRSA CI-M was incubated with 25 µg/ml Norfloxacin (NOR) in the absence or presence of 25 µg/ml AEA for 2 h at 37 °C. Then the norfloxacin was removed, and the amount of norfloxacin retained in the bacteria was measured after 3 h on flow cytometry. (B) PBP2a expression levels (upper panel) in crude membrane extracts of MDRSA CI-M treated with 50 µg/ml AEA for 2 h in comparison to control. Two different samples of control and AEA-treated bacteria are shown. Lower panel: Silver staining of the same samples in the polyacrylamide gel as loading control. (C) The relative PBP2a expression level in AEA-treated versus control MDRSA CI-M as measured from 4 different samples using the Photoshop software on the PBP2a panel shown in (B). (D) Inhibition of cell wall synthesis by AEA. MDRSA CI-M was incubated with 50 μg/ml AEA and/or 50 μg/ml methicillin (MET) for 2 h, and then incubated with Sortase Substrate I, FRET, for 2.5 h. At the end of incubation, the fluorescence intensity (Ex/Em = 340/490) of the washed bacteria was measured in a Tecan plate reader. * p < 0.05.