Origin version 8

N2a cell apoptosis was detected via flow cytometry using an Annexin V/PI double staining kit (BD Biosciences) according to the manufacturer's instructions. N2a cells were collected and then washed twice with ice-cold PBS. Next, the cells were resuspended in binding buffer and stained with Annexin V-FITC and PI at room temperature for 15 min in the dark. Finally, flow cytometry was performed with a Coulter^® EPICS XL instrument (Beckman Coulter, Inc.). The data of flow cytometry were analyzed using Flowing version 2.5.1 software (Turku Bioscience) and Origin version 8 software (OriginLab). The apoptosis rate was calculated as the percentage of early apoptotic cells to total cells.

The strains (A total of 10 NDM-1 positive non-duplicate K. pneumoniae isolates, which were obtained from a teaching hospital of Zhengzhou University, Zhengzhou, China) were grown overnight (incubated at 37 °C with aeration at 225 rpm) with Shaker (ZWY-1102C, Zhicheng Analytical Instrument Manufacturing Co., Ltd., Shanghai, China). On the next day, the bacterial solution was diluted 1:10,000 with MHB medium, and placed on a constant temperature shaker at 37 °C for 225 rpm to continue growth for 2 h, after which different concentrations of MIC compounds and meropenem were added. At this time, it was 0 h, 100 μL of the sample solution was taken out from the EP tube, centrifuged at 10,000×g in a centrifuge, the supernatant was discarded, and a sterile 96-well plate was taken and diluted with 1 × PBS buffer. Diluted 10 times in sequence, and took 10 μL of the sample droplet from the diluted well and added it to the MHA solid medium to mark it. This was the colony count at 0 h. At this time, according to the above sampling method, the colony counts were performed for 1, 2, 3, to 24 h, and the time sterilization curve was obtained with Origin version 8.0 (OriginLab, Northampton, MA, USA). The bacterial colonies were counted and results represented in log₁₀ (CFU/mL) using the origin 8.0. And photos the bacteria control for 24 h.