Novel Genetically Engineered Probiotics for Targeted Elimination of Pseudomonas aeruginosa in Intestinal Colonization

The intestinal carriage rates of Pseudomonas aeruginosa are notably elevated in immunosuppressed individuals and hospitalized patients, increasing the risk of infection and antibiotic-associated diarrhea. A potential solution to this issue lies in autonomous antibacterial therapy, remaining inactive until a pathogen is detected, and releasing antibacterial compounds on demand to eliminate the pathogen. This study focuses on the development of genetically engineered probiotics capable of detecting and eradicating P. aeruginosa by producing and secreting PA2-GNU7, a P. aeruginosa-selective antimicrobial peptide (AMP), triggered by the presence of P. aeruginosa quorum-sensing molecule N-(3-oxododecanoyl)-_L-homoserine lactone (3OC₁₂HSL). To achieve this goal, plasmid-based systems were constructed to produce AMPs in response to 3OC₁₂HSL and secrete them into the extracellular medium using either the microcin V secretion system or YebF as a carrier protein. Following the transfer of these plasmid-based systems to Escherichia coli Nissle 1917 (EcN), we successfully demonstrated the ability of the engineered EcN to express and secrete PA2-GNU7, leading to the inhibition of P. aeruginosa growth in vitro. In addition, in a mouse model of intestinal P. aeruginosa colonization, the administration of engineered EcN resulted in reduced levels of P. aeruginosa in both the feces and the colon. These findings suggest that engineered EcN holds promise as a potential option for combating intestinal P. aeruginosa colonization, thus mitigating the risk of future endogenous infections in vulnerable patients.