Fig. 4. Sphingosine has antimicrobial activity against clinical P. aeruginosa isolates. Sphingosine was added to P. aeruginosa 762 (A) or P. aeruginosa ATCC19660 (B) at a final concentration of 100 µM. Samples were incubated for 4 h, then diluted and plated overnight. CFUs were counted the next day. n = 9 samples/group, spread across 3 biologically independent experiments.   p < 0.05 vs 0 µM (Student t test).