Ultrashort lipo-tetrapeptide with potent antibacterial activity and local therapeutic effect against Staphylococcus aureus

Mastitis in dairy cows is a common infectious disease on dairy farms and a major danger to the dairy industry. The harmful bacteria with the greatest clinical isolation rate are Staphylococcus aureus. As a result, bacterial mastitis in dairy cows can lead to decreased milk output, quality, and costs. Traditional antibiotics are currently used to treat mastitis in dairy cows. Nonetheless, long-term usage of high doses of antibiotics increases the risk of the establishment of drug-resistant strains, and the problem of drug residues is becoming more prevalent. We investigated the antibacterial effects of varying molecular side chain length lipopeptides on Staphylococcus aureus ATCC25923 and GS1311 using five tetrapeptide ultrashort lipopeptides developed and synthesised in this study. To evaluate the application value of the synthesized lipopeptides in the prevention and treatment of mastitis, the lipopeptides with the best antibacterial action were chosen for safety testing and a mouse mastitis model treatment test. Three of the lipopeptides produced have strong antibacterial properties. Within the drug's safe concentration range, C16KGGK has an excellent antibacterial action and can have a therapeutic influence on mastitis induced by Staphylococcus aureus infection in mice. The findings of this study can be used to develop new antibacterial medications and their therapeutic application in the treatment of mastitis in dairy cows.