Optimized Charge/Hydrophobicity Balance of Antimicrobial Peptides Against Polymicrobial Abdominal Infections.

Antimicrobial peptides (AMPs) potentially serve as ideal antimicrobial agents for the treatment of polymicrobial abdominal infections due to their broad-spectrum antimicrobial activity and excellent biocompatibility. However, the balance of chain length, positive charges and hydrophobicity on the antimicrobial activity of AMPs are still far from being optimal. Herein, we designed a series of AMPs ([KX] n -NH 2 , X = Ile, Leu or Phe, n = 3, 4, 5 or 6) with varied charges and hydrophobicity for the treatment of polymicrobial abdominal infections. Specifically, [KI] 4 -NH 2 peptide exhibited the best in vitro antimicrobial activity against Gram-positive and -negative bacteria, as well as fungal strains. Based on the good cell biocompatibility, [KI] 4 -NH 2 peptide was found to have negligible in vivo toxicity at the dosage of up to 28 mg k -1 g. Furthermore, great in vivo therapeutic efficacy of [KI] 4 -NH 2 peptide against S. typhimurium was demonstrated in the mice abdominal infection model. The design of short sequence of antimicrobial peptides with a charge/hydrophobicity balanced structures provides a simple and efficient strategy for potential clinical applications of antimicrobial peptide-based biomaterials in a variety of bacterial infection diseases. This article is protected by copyright. All rights reserved.