Researchers found that a virus‑derived peptide called gp28 can kill the tough bacteria Pseudomonas aeruginosa, break down its protective biofilm, and make the antibiotic tobramycin work better. It works at a concentration of about 109 µg/mL and shows promise as a new kind of antimicrobial, but it’s still early‑stage research and not yet a product you can buy or use.

<i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>) is a gram-negative bacterial pathogen commonly associated with nosocomial infections. Treatment of <i>P. aeruginosa</i> infections is notoriously difficult due to biofilm formation and antibiotic resistance. Antimicrobial peptides (AMPs) are thought to be promising new antimicrobials. Gp28, a phage-derived AMP, is a novel class of characterized phage AMPs with activity against <i>Escherichia coli</i> in a manner similar to the human peptide LL-37. LL-37 exhibits strong antimicrobial activity against <i>P. aeruginosa</i> as well as biofilm disruption and synergy with certain antibiotics posing the question whether gp28 could act similarly. Antibacterial activity of gp28 against <i>P. aeruginosa</i> was established using growth inhibition assays, with minimum inhibitory concentration calculated. Biofilm disruption was assessed using crystal violet staining and scanning electron microscopy. Combined treatment of gp28 with tobramycin against <i>P. aeruginosa</i> was measured using a modified time-kill assay at sublethal concentrations. Gp28 inhibits <i>P. aeruginosa</i> planktonic growth, with a minimum inhibitory concentration of 109 &#x3bc;g mL^-1 and disrupts established biofilms. We demonstrate that gp28 increases the susceptibility of <i>P. aeruginosa</i> to tobramycin. Gp28 demonstrates potential for development as a putative therapeutic agent against a clinically resistant <i>P. aeruginosa</i> strain either alone or in combination with the frontline antibiotic tobramycin.