Antibacterial and Antibiofilm Activities of Ceragenins against Pseudomonas aeruginosa Clinical Isolates

Objectives: Pseudomonas aeruginosa can cause life-threatening infections that are difficult to treat due to its high resistance to antibiotics and its ability to form antibiotic tolerant biofilms. Ceragenins, designed to mimic the activities of antimicrobial peptides, represent a promising new group of antibacterial agents that display potent anti-P. aeruginosa activity. The aim of this study was to evaluate the antibacterial and antibiofilm activities of ceragenins in comparison to colistin and ciprofloxacin against P. aeruginosa strains. Materials and Methods: Biofilm formation and determination of minimum inhibitory concentration (MIC) values of ceragenins (CSA-13, CSA-44, CSA-131, and CSA-138), ciprofloxacin, and colistin were evaluated against 25 P. aeruginosa isolates. Four good biofilm-producing strains were chosen for biofilm studies, and sessile MICs and inhibition of molecule adhesion and biofilm formation were evaluated. Results: The MIC 50 (mu g/mL) values of CSA-13, CSA-44, CSA-131, CSA-138, ciprofloxacin, and colistin were 8, 8, 8, 16, 1, and 2, respectively. The sessile MICs for molecules were greater than planktonic MICs. CSA-13, CSA-44, and CSA-131 were more efficient after 4 h incubation while CSA138, ciprofloxacin and colistin were more efficient after 1 h incubation. The most efficient agent for inhibition of adhesion was colistin (up to 45%). CSA-131, CSA-138, and colistin were the most efficient agents for inhibition of biofilm formation (up to 90%). Conclusion: Our study highlights the potential of CSA-131 and CSA-138 as potential alternative agents to conventional antibiotics for the eradication of biofilms of P. aeruginosa.