Antimicrobial effects of novel Hermetia illucens peptides

Antimicrobial resistance represents a significant global health challenge, implicated in nearly 5 million deaths per year. This study investigates the antimicrobial properties of selected peptides derived from the Black Soldier Fly (BSF), identified in silico. Ten synthesized peptides were evaluated in vitro against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), and fungi (Aspergillus fumigatus, Candida albicans). Cytotoxicity was assessed using human lung fibroblasts and red blood cells. Among the peptides, Hill_BB_C7176 demonstrated broad-spectrum antibacterial activity, no cytotoxicity and low hemolytic activity (IC₅₀: 31.6 - >32 µM). The peptide displayed rapid bactericidal activity achieving complete eradication at 8× its minimal inhibitory concentration. Propidium iodide uptake increased in a concentration dependent manner, indicating membrane permeabilization contributing to antibacterial activity. In addition, Hill_BB_C7176 exhibited strong binding affinity to lipopolysaccharide (lipid A). In vivo, Hill_BB_C7176 improved survival of Galleria mellonella larvae infected with S. aureus and E. coli, showing similar survival outcomes to reference antibiotics under the experimental conditions tested. These findings highlight the antibacterial potential of BSF-derived antimicrobial peptides, particularly Hill_BB_C7176, supporting the further research on the antibacterial activity of BSF antimicrobial peptides.