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

## TL;DR

A new antimicrobial peptide from horseflies shows promise in fighting drug-resistant Klebsiella pneumoniae infections in mice.

## Contribution

The discovery of CEC-TY1, a non-toxic antimicrobial peptide from horsefly saliva, effective against CRKP both in vitro and in vivo.

## Key findings

- CEC-TY1 exhibited antibacterial activity against gram-negative bacteria at concentrations up to 100 μg/mL.
- CEC-TY1 improved survival rates in mice infected with CRKP and reduced harmful inflammation.
- The peptide showed no cytotoxicity or hemolytic activity, making it a safe candidate for therapeutic use.

## Abstract

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.

Antimicrobial 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.