Importantly, the efficacy of Esc(1–21)-1c in reducing lung bacterial burden at 24 hours after Pseudomonas challenge revealed to be comparable (about 2-log reduction of lung burden) to that found for the last resort of antibiotics, i.e. colistin, in another set of experiments (Fig. 5b). In comparison, the human LL-37 almost completely lost its antimicrobial potency (Fig. 5b), presumably due to its higher susceptibility to proteolytic degradation29.