Genetically modified bacteriophages in applied microbiology

Abstract

Summary Bacteriophages represent a simple viral model of basic research with many possibilities for practical application. Due to their ability to infect and kill bacteria, their potential in the treatment of bacterial infection has been examined since their discovery. With advances in molecular biology and gene engineering, the phage application spectrum has been expanded to various medical and biotechnological fields. The construction of bacteriophages with an extended host range or longer viability in the mammalian bloodstream enhances their potential as an alternative to conventional antibiotic treatment. Insertion of active depolymerase genes to their genomes can enforce the biofilm disposal. They can also be engineered to transfer various compounds to the eukaryotic organisms and the bacterial culture, applicable for the vaccine, drug or gene delivery. Phage recombinant lytic enzymes can be applied as enzybiotics in medicine as well as in biotechnology for pathogen detection or programmed cell death in bacterial expression strains. Besides, modified bacteriophages with high specificity can be applied as bioprobes in detection tools to estimate the presence of pathogens in food industry, or utilized in the control of food‐borne pathogens as part of the constructed phage‐based biosorbents.

Promises and pitfalls ofin vivoevolution to improve phage therapy

“…Protective bacterial secretions include more than just bacterial capsules, such as the chemically complex matrices in biofilms and aggregates [21,28,37,45–47]. Phage-encoded enzymes do not necessarily exist for all bacterial matrix components, but enzyme-encoding genes from other sources (bacteria, fungi) can be engineered into and expressed from phages to achieve degradation [e.g., 21,48,49].…”

“…One alternative is to isolate wild phages that grow on the resistant hosts, then use those in the therapeutic cocktail. Engineering is another possibility for generating resistance-blocking phages [49,68–70]. Advance selection of resistance-blocking phages is possible because bacterial evolution to resist a single phage often follows a common molecular pathway, enabling the investigator to replicate in vitro the within-patient arms race.…”

Phage engineering: how advances in molecular biology and synthetic biology are being utilized to enhance the therapeutic potential of bacteriophages

“…There have been a number of exciting developments in the field, with only a selection of these developments highlighted in this review. There are significant differences between even a non-replicative phagemid and an antimicrobial drug treatment; how these differences are reconciled within the current pharmaceutical testing, licensing and 'Good Manufacturing Practices' (GMP) framework will be interesting and possibly significantly impact the direction of future applied phage research [36,77]. Also, many of the phage engineering solutions discussed here would give rise to what would be considered a geneticallymodified organism (GMO) and as such the licensure and clinical use of these phage would be tightly regulated.…”

Bacteriophage Based Biosensors: Trends, Outcomes and Challenges

“…While, this DNA in the host genome is called a prophage, the lysogenic cycle can continue indefinitely, except in some cases, such as adverse conditions of the environment and bacteria exposure to stress [14]. Consequently, the bacteriophage used like bio-probe in biosensor devises offer several advantages, such as (1) specificity to host bacteria, consequently efficient bacteria screening [15], (2) easy to generate mass quantities of progeny phages, due to their short replication time, (3) ability to tolerate critical conditions, such as organic solvents and large range of pH and temperature [16]. It is important to understand the characteristics of phages, such as the physical and chemical properties, in order to design the biosensor platform able to bind the phage without losing their ability to recognize the bacteria target.…”