Antimicrobial Peptides against Multidrug-Resistant <i>Pseudomonas aeruginosa</i> Biofilm from Cystic Fibrosis Patients

Abstract

Lung infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and is mainly dominated by <i>Pseudomonas aeruginosa</i>. Treatment of CF-associated lung infections is problematic because the drugs are vulnerable to multidrug-resistant pathogens, many of which are major biofilm producers like <i>P. aeruginosa</i>. Antimicrobial peptides (AMPs) are essential components in all life forms and exhibit antimicrobial activity. Here we investigated a series of AMPs (d,l-K₆L₉), each composed of six lysines and nine leucines but differing in their sequence composed of l- and d-amino acids. The d,l-K₆L₉ peptides showed antimicrobial and antibiofilm activities against <i>P. aeruginosa</i> from CF patients. Furthermore, the data revealed that the d,l-K₆L₉ peptides are stable and resistant to degradation by CF sputum proteases and maintain their activity in a CF sputum environment. Additionally, the d,l-K₆L₉ peptides do not induce bacterial resistance. Overall, these findings should assist in the future development of alternative treatments against resistant bacterial biofilms.