Antimicrobial peptide CEC-TY1: a potential antibacterial drug against carbapenem-resistant Klebsiella pneumoniae.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections in hospitals and the issues arising from their rapid spread have become significant public health challenges. Therefore, a new class of effective and safe antibacterial drugs is urgently required. In this study, we identified an antimicrobial peptide in the cecropin family, cecropin-TY1 (CEC-TY1), from the salivary glands of the horsefly. CEC-TY1 showed significant antibacterial activity against gram-negative bacteria, at concentrations up to 100 μg/mL, with no observed cytotoxicity or hemolytic activity against cells. Moreover, CEC-TY1 protected mice from lethal infections of CRKP in vivo, improving the survival rate of the infected mice. This peptide also alleviated excessive and harmful inflammatory responses by inhibiting the production of interleukin (IL)-6, tumor necrosis factor-α, and IL-1β.IMPORTANCEAntimicrobial peptides are a promising alternative to antibiotics in the current antibiotic resistance crisis. Specifically, the antimicrobial peptide cecropin-TY1 (CEC-TY1), identified in the salivary glands of horseflies, showed significant antibacterial activity against carbapenem-resistant Klebsiella pneumoniae (CRKP), both in vitro and in vivo. CEC-TY1 also has selective toxicity and low hemolytic activity and is therefore a potential therapeutic agent for acute CRKP infection.