Genetically Engineered Phages: a Review of Advances over the Last Decade

Abstract

SUMMARYSoon after their discovery in the early 20th century, bacteriophages were recognized to have great potential as antimicrobial agents, a potential that has yet to be fully realized. The nascent field of phage therapy was adversely affected by inadequately controlled trials and the discovery of antibiotics. Although the study of phages as anti-infective agents slowed, phages played an important role in the development of molecular biology. In recent years, the increase in multidrug-resistant bacteria has renewed interest in the use of phages as antimicrobial agents. With the wide array of possibilities offered by genetic engineering, these bacterial viruses are being modified to precisely control and detect bacteria and to serve as new sources of antibacterials. In applications that go beyond their antimicrobial activity, phages are also being developed as vehicles for drug delivery and vaccines, as well as for the assembly of new materials. This review highlights advances in techniques used to engineer phages for all of these purposes and discusses existing challenges and opportunities for future work.

Roles for Intestinal Bacteria, Viruses, and Fungi in Pathogenesis of Inflammatory Bowel Diseases and Therapeutic Approaches

“…The effects of bacteriophage on bacteria might be exploited therapeutically 59 . Interest in phage-based therapies was initially hampered by inadequately controlled trials and the discovery of antibiotics.…”

Phage therapy: awakening a sleeping giant

“…A plasmid can be designed to encode antimicrobial peptides and toxin proteins that can be delivered by a phagemid to cause nonlytic bacterial death [38]. Instead of directly killing bacteria, phagemids can be used to enrich, for example with antibiotic-sensitized populations, by delivering a sequence-specific CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) system [13,39,40]. CRISPR RNAs can be programmed to target antibiotic-resistant genes on bacterial born plasmids, which when delivered by phagemids can reverse antibiotic resistance and eliminate the transfer of resistance between strains [39][40][41].…”

“…Accordingly, the progression in the development of phage therapies has grown steadily across a wide variety of diseases (Table 1). Recently, advances in genome engineering have led to the design of semisynthetic and synthetic phages with specialized antibacterial features, drastically broadening the breadth of phage therapies [13]. This review provides a general overview of phage therapy, both natural and syntheticbased, and summarizes the current progress in defining the ability of phages to provoke mammalian host immune responses and bacterial resistance.…”

Quantitative and synthetic biology approaches to combat bacterial pathogens

“…To facilitate detection and quantification, engineered phages have been equipped with a wide range of reporter genes, which code for fluorescence [57] or enzymatic activities [58-60]. These readouts are often more rapid to quantify and require less steps than plaque assays or immunoassays [61]. In addition to detection, engineered phages can be used to quantify bacterial response to antibiotic treatments with high sensitivity [62-64].…”