Engineering Short Antimicrobial Peptides to Specifically Target Fusobacterium nucleatum in the Mixed Microbial Population

Antimicrobial peptides (AMPs) are becoming next-generation alternative antibacterial agents because of the rapid increase in resistance in bacteria against existing antibiotics, which can also be attributed to the formation of resilient biofilms. However, their widespread use is limited because of their poor absorption, higher dosage requirements, and delayed onset of the bioactivity to elicit a desired response. Here we developed a short AMP that specifically targeted Fusobacterium nucleatum. We conjugated 23R to a statherin-derived peptide (SDP) through rational design; this conjugate binds to FomA, a major porin protein of F. nucleatum. The SDP-tagged 23R exhibited rapid and highly specific bactericidal efficacy against F. nucleatum. Further, IC50 values were in the nanomolar range, and they were 100-fold lower than those obtained with unconjugated 23R. In a human gut microbiota model, 0.1 nM SDP–23R achieved 99% clearance of F. nucleatum ATCC 25586 without markedly altering resident microbiota. Here we demonstrated that binding-peptide-coupled AMPs show increased killing efficacy and specificity for the target pathogen without affecting the resident microbiota.