Toward Rational Engineering of Phage to Combat Multidrug-Resistant Pathogens

The global threat of multidrug resistant (MDR) bacterial pathogens requires rapid development of new antimicrobials and has revitalized interest in exploiting lytic bacteriophage to treat human infections. Challenges presented by traditional phage therapy, involving cocktails of individual phages, include formulation complexity to overcome inherent narrow host-range specificity, accessibility to bacterial pathogens embedded within the exopolysaccharide matrix (biofilms), development of phage-resistance and the associated uncertainty of the regulatory approval framework, have limited successful clinical adoption. Synthetic biology driven engineering of phage, to impart key drug-like properties, provides an approach to overcome these traditional limitations. ~300 Pseudomonas aeruginosa (P.a.) MDR clinical isolates were obtained and a large collection of lytic P.a. phage was established.  Next generation sequencing, developed bioinformatics analysis and an advanced genetic toolbox were systematically employed to quickly correlate diverse underlying genetic determinants with phenotypic properties to inform and power a design/build/test pipeline of accelerated, iterative phage engineering.  Enabled by rapid construction of engineered P.a. phage genomes and direct transformation into P.a. hosts for lytic phage production, this platform has produced engineered phage chassis with designed, expanded host-range and enhanced lytic activity.  Ongoing development of this platform focuses upon overcoming host resistance mechanisms to produce engineered phage therapy product candidates with defined and enhanced properties for clinical applications.