An antimicrobial peptide expression platform for targeting pathogenic bacterial species

Bacteriocins are antimicrobial peptides that are naturally produced by many bacteria. They hold great potential in the fight against antibiotic resistant bacteria, including ESKAPE pathogens. However, they often have low stability in vivo and therefore, may not be effective when administered orally. Engineered live biotherapeutic products (eLBPs) that secrete bacteriocins can be created to deliver bacteriocins directly at the site of infection. Here we develop a modular bacteriocin secretion platform that can be used to express and secrete multiple bacteriocins from non-pathogenic Escherichia coli host strains. As a proof of concept we create Enterocin A and Enterocin B secreting strains that show strong antimicrobial activity against Enterococcus faecalis and Enterococcus faecium, and characterise this activity in both solid culture and liquid co-culture. We then develop a Lokta-Volterra model that can be used to capture the interactions of these competitor strains. We show that simultaneous exposure to EntA and EntB can delay the point of Enterococcus growth. Our system has the potential to be used as an eLBP to secrete additional bacteriocins for the targeted killing of other pathogenic bacteria.