Bacteriophages were first brought to light in 1915 when Dr. d’Herelle, a French Canadian microbiologist working at the Paris Institut Pasteur, coined them as viruses who infect bacteria. These viruses have two life cycles: lytic and lysogenic. In both cases, they infect the bacterium by attaching and injecting their DNA into the cell. Once matured, lytic phages rupture the bacterium while lysogenic phages integrate their DNA into the bacterium’s chromosome and later undergo induction, where the phage genome is excised from the chromosome, parting with some bacterial DNA.
Most of the research conducted on phage therapy stems from Eastern Europe since not many people agreed on the viral nature of bacteriophages in the West and opted to pursue the road of antibiotics instead. However, research has shown that bacteriophages are greatly beneficial. Dr. d’Herelle himself developed many efficient phage formulations sold by the company that later became known as L’Oréal. Imagine the many benefits of a L’Oréal phage foundation for the skin to combat acne!
Studies carried out in Eastern Europe have shown that bacteriophages are highly specific, being able to target different types of bacteria, as well as different strains. They replicate only where the bacteria are found, with no serious side effects. It has also been shown that bacteria who develop a resistance to phages are susceptible to phages sharing similar tropism and other bacteriophages can also be quickly grown to destroy the newly resistant strains. Phage therapy has been applied in various methods: topically, orally, rectally and intravenally without serious complications. It has been used to treat a wide variety of diseases such as urinary tract infections, vaginitis, Cystic Fibrosis (CF) as well as fastidious S. aureus skin lesions with or without antibiotics.
A recent example of resurfacing phage therapy research is that of an in vivo study led by Dr. Debarbieux of the Institut Pasteur with promising results. They used phage therapy to treat immunocompetent mice inoculated with a mucoid strain of Pseudomonas aeruginosa isolated from CF patients and found that a 4-day treatment consisting of a single dose of phage solution was enough to allow 100% survival. For all these reasons, phage therapy is highly attractive, and even more when it comes to antibiotic-resistant microbes, like MRSA. Perhaps, phages could be used in the future to treat cumbersome illnesses such as Lyme disease and tuberculosis.
Bacteriophages have also been used in cancer therapy. Phages are known to affect the tumor surroundings by influencing cytokine production, making the tumor more sensitive to cancer therapeutics. They have also been used as part of a technique called phage display where they can deliver genome-encoded proteins or chemically-linked nanomedicines. Bacteriophages could also help us develop antibiotics in the future by performing screens that identify phage compounds deterring bacterial growth or development. From then, medical chemistry can be utilized to design drugs mimicking these proteins. With so many different areas to explore, phage therapy is an exciting field worth exploiting! References 1. Sulakvelidze, A et al. 2001. Minireview: Bacteriophage Therapy. Antimicrobial agents and Chemotherapy 45(3): 649-659 2. Summers WC. 2001. Bacteriophage therapy. Annual Reviews of Microbiology 55: 437-451 3, Morello et al. 2011. Pulmonary bacteriophage therapy on Pseudomonas aeruginosa Cystic Fibrosis Strains: first step towards treatment and prevention. PLoS ONE 6(2): e16963. 4. Kaur, T et al. 2012. Review article: Immunocompatibility of bacteriophages as nanomedicines. Journal of Nanotechnology 2012: 1-13. 5. Vazquez et Villaverde. 2010. Engineering building blocks for self-assembling protein nanoparticles. Microbial Cell Factories 9(1): 101
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