Engineered bacteriophage as a platform to deliver nucleic acid based therapeutics to bacteria to disperse biofilms in implant-associated infections such as prosthetic joint infections

Abstract Bacteriophages are viruses that specifically and solely infect bacteria and are a natural platform delivery system of genetic information encoded by nucleic acids to bacteria Lytic bacteriophages do not integrate their DNA into the bacterial chromosome but replicate independently and ultimately kill their host bacteria In the early andapos s bacteriophages were used to fight infections in humans but largely fell to the wayside after the discovery of antibiotics in the andapos s Only in Eastern Europe and the former Soviet Republics are bacteriophages still considered as effective therapeutic agents With the antibiotic armamentarium currently challenged by the combination of increasing antibiotic resistance and a dearth of new investment and discovery in new classes of antibiotics natural bacteriophage therapy is experiencing a renaissance Along with this renaissance in bacteriophage therapy advances in systems and synthetic biology now enable exquisite engineering of bacteriophage genomes to introduce nucleic acid therapeutics to alter the physiology pathogenicity virulence and antibiotic sensitivity of targeted bacterial species Bacteriophage can thus be designed to deliver genetic payloads to achieve specific desired effects such as enhancing antibiotic killing by genetic repression of DNA repair mechanisms the self generation of antimicrobial peptides and proteins and expression of enzymes to degrade bacterial biofilms Biofilm associated infections are particularly difficult to treat due to the physical and physiological barriers biofilms pose to antimicrobial agents and host defenses Biofilms are central to the pathogenesis of many serious clinical infections and often colonize foreign body surfaces such as in prosthetic joint infections PJI The annual cost of PJI to US hospitals in was $ M and is projected to increase to $ B by Much of this cost is for surgical replacement of infected prostheses due to the failure of medical treatment Failure of medical treatment is most problematic in device infections caused by S aureus due to its virulence and rapid biofilm formation This proposal seeks to improve medical treatment for PJI caused by S aureus by utilizing engineered bacteriophage to deliver nucleic acid therapeutics to the bacteria encoding biofilm degrading enzymes to disperse the protective biofilm Removal of the biofilm will reduce the inherent tolerance of bacteria to antimicrobial therapy improve medical treatment outcomes and thereby reduce surgical intervention prosthesis replacement and the associated health costs and patient burden Project Narrative Bacteriophages are viruses that infect and kill only bacteria Using synthetic biology bacteriophages are a natural platform for delivering engineered genes to bacteria to alter their physiology and function to make bacteria more sensitive to antibiotics This project will engineer a bacteriophage to deliver gene payloads encoding enzymes to remove the biofilm a surface associated aggregate of bacterial cells in a gelatin like slime that protects bacteria from antibiotics and host defense on prosthetic joints i e knees and hips infected with Staphylococcus aureus as an adjuvant to standard antibiotic therapy