NAVAL MEDICAL RESEARCH UNIT (SAN ANTONIO) FORT SAM HOUSTON TX FORT SAM HOUSTON United States
Approvals of novel antibiotics are uncommon, especially for Gram-negative bacteria, though the rates of multidrug resistant infections are increasing. This generates a gap between our need for antibiotics and the number of antibiotics available. One way to address this widening gap is to search for antimicrobial peptides, small proteins with broad spectrum antibacterial effects. We tested two antimicrobial peptides the Dermaseptin derivatives K4K20S4 and K4S41-15, for efficacy against two laboratory strains and two clinical isolates of Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, in two types of minimal media and two types of complete media. Both antimicrobial peptides are more effective against P. aeruginosa grown in minimal media than in complete media. Overall, K4K20S4 and K4S41-15 are just as effective against multidrug resistant clinical isolates as they are against laboratory strains. Both K4K20S4 and K4S41-15 can be effective against multidrug resistant isolates and laboratory strains of P. aeruginosa. The shorter peptide, K4S41-15, is both less cytotoxic and more efficacious than K4K20S4, making it an especially good candidate for future antibacterial development.