Phage-based approaches targeting MDR/XDR High-Risk clones of Pseudomonas aeruginosa

The current antibiotic resistance crisis, calls for the development of new strategies to tackle the emergence and dissemination of antimicrobial resistance (AMR). The escalating concerns regarding this rapid increase in AMR have prompted the World Health Organisation (WHO) to develope a list of priority pathogens, requiring the urgent development of new and effective treatments. Within the most critical group lies multi-drug resistant (MDR) Pseudomonas aeruginosa, a versatile opportunistic human pathogen responsible for a wide spectrum of acute and chronic infections. In response to these challenges, phage therapy (PT) has re-emerged as a promising alternative in combatting these difficult-to-treat infections. However, the practical application of phages is often limited by our knowledge of phage biology and phage-host interactions.

We curated a representative and comprehensive collection of 90 diverse and unique P. aeruginosa phages. These phages belong to 17 different genera and were systematically characterized for their efficacy against a panel of relevant MDR/XDR P. aeruginosa strains. This approach facilitated the comparative evaluation of phenotypic and genotypic traits involved in phage-host interactions, including the background of the strains, their prophages, the impact of anti-phage defense mechanisms, and phage receptors. Providing insights for the selection of phages for phage therapy.

Furthermore, a fully synthetic phage platform was developed by re-purposing an Escherichia coli phage that can carry and deliver custom made DNA therapeutic payloads. This phagemid platform can be produced in an avirulent E. coli strain and allows design and delivery of anti-Pseudomonas payloads to different P. aeruginosa strains through tail fiber engineering. Successful delivery of different cargos with delivery range profiles dictated by the chimeric fibers was shown as well as therapeutic functions based on the delivered payloads including CRISPR spacers, lysis genes or anti-virulence factors. Showing the adaptability, versatility and flexibility of phage-based platforms.