Figure 6.

Membrane permeability of K. pneumoniae B9 does not change with treatment of 2 μg/mL colistin or compound alone but increases significantly under lethal combination conditions. The percent increase in membrane permeability was calculated by comparing SYTO9: propidium iodide fluorescence ratios of treated cells to untreated cells. Error bars represent standard error of at least two independent biological samples from experiments conducted on separate days. Note: treatment conditions “+2048 μg/mL colistin” and “+2.5 μM novobiocin + 2 μg/mL colistin” have standard error below 1%.