Leveraging localised mutations to expand the host range of phage cocktails against Pseudomonas aeruginosa

Bacteriophages are enigmatic biological entities that have co-existed with bacteria for millions of years. The therapeutic potential of phages is enormous but is often limited by their very high host specificity. This project aims to develop and test an approach to quickly generate phage variants with expanded host range. 

In a recently published Lancet study on antibiotic-resistant bacteria Pseudomonas aeruginosa was once again classified as one of the high priority pathogens, indicating the urgent need to address this public health threat. Bacteriophages are attractive antibacterial agents – they are effective, harmless to humans, and do not affect normal microbiota. This makes phage therapy an attractive alternative to antibiotics. One of the main limitations of phage therapy is a narrow host range of many bacteriophages. In this project we intend to develop efficient therapeutic preparations based on phiKMVviruses.

This project aims to increase the frequency of mutations in phage receptor-binding proteins, helping to quicker generate new mutant phage particles. A three-pronged approach will be applied: a) various conditions of phage growth will be tested with the aim to increase region specific mutagenesis; b) we will develop approaches to select for mutants targeting multiple virulent strains; c) we will engineer modified phage DNA polymerases providing optimal mutational frequencies. The innovative approach described herein relies on the use of already well characterised phages capable of quickly extending their host range, helping to significantly reduce both time and costs required for phage cocktail preparations against pathogenic bacteria.