Development of a New Ten Amino Acid Antimicrobial Peptide (AMP) Against Extensively Drug-resistant Bacteria, Pseudomonas aeruginosa and Acinetobacter baumannii

Growing microbial resistance to conventional antimicrobial agents reveals the need for development of novel and alternative therapeutic strategies. In the present study, we developed a new ten amino acid antimicrobial peptide (AMP) and evaluated its antibacterial activity against extensively drug-resistant bacteria, Pseudomonas aeruginosa (P. aeruginosa) and Acinetobacter baumannii (A. baumannii). After synthesis of the AMP, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested using different concentrations (2 to 128 ng/mL) of the AMP. Afterwards, the cell viability and toxicity of the AMP were investigated on primary fibroblast cells using MTT and trypan blue exclusion assays with different concentrations (2 to 128 ng/mL) of the AMP, respectively. The AMP showed MICs≥0.023 and 0.046 ng/mL for P. aeruginosa and MICs≥0.18 ng/mL for A. baumannii. In addition, the AMP exhibited MBCs≥0.05 and 0.09 ng/mL for P. aeruginosa and MBCs≥0.04 and 0.045 ng/mL for A. baumannii. Results from the disk diffusion assay showed 12 and 16 mm for P. aeruginosa and 9 mm for A. baumannii. In vitro cell cytotoxicity and hemolytic activity assays confirmed the safety profile of the AMP (no toxicity or hemolytic activities at concentrations ≤8 ng/mL). Our results suggested that the AMP developed in this study is a reliable and safe antimicrobial agent for the treatment of extensively drug-resistant bacteria, P. aeruginosa and A. baumannii.