Synthetic epidermicin NI01 can protect Galleria mellonella larvae from infection with Staphylococcus aureus

Objectives:EpidermicinisanovelantimicrobialpeptidethathaspotentactivityagainstGram-positivepathogens, including methicillin-resistant Staphylococcus aureus, and it may have potential for use in therapy for infections causedbythesebacteria,thoughinvivoefficacyneedstobedemonstrated.Galleriamellonellalarvaehaverecently beenintroducedasanalternativeinvivomodeltomammaliansystemsandhereweexaminedtheabilityofasynthetic version of epidermicin to protect G. mellonella larvae from infection with S. aureus strains. Methods: G. mellonella larvae were infected with �2.5 ×10 6 cells per larva and then treated with vancomycin or epidermicin and survival recorded over a 120 h period. Vancomycin was used at up to 50 mg/kg and epidermicin at up to 200 mg/kg with administration of treatments occurring 0‐2 h post-infection. Results: Epidermicin was shown to be non-toxic and did not stimulate the G. mellonella immune system. When administered 2 h post-infection at a maximum dose of 200 mg/kg, epidermicin significantly increased survival in larvae; however, altering the dosage regimen by reducing the time to administration to 30 min post-infection increased the potency of the peptide.