Bacteriophages, or phages for short, are viruses that infect bacteria, and are considered the most abundant organisms on the planet with trillions of particles. Phage therapy is seen as a promising alternative to antibiotics, especially as antibiotics have seen an increasing amount of bacterial resistance. I participated in a research lab where we worked with bacteriophages during these past few months, and learned a lot about phages and its potential for combatting bacterial infection.

Phages all have a nucleic acid genome that is encapsulated by a protein called a capsid. This functions to protect the phage’s genome and help it function properly. Given this structure, phages are classified as viruses, specifically those that infect bacteria.

There are trillions of these particles on earth that are especially abundant in the soil, and have shown to be helpful for humans as it can act as an extra line of defense for our immune system. It’s also seen as a potential alternative to antibiotics.

To understand phage therapy, it’s important to understand the processes of replication that phages undergo: the lytic and lysogenic cycles. Lytic phage infections specialize in destroying cells or “hijacking” them — it’s a direct attack on cells. Lysogenic infections, on the other hand, are more “latent”, long-term infections that pass down from cell generation to generation through replication.

Phage therapy uses both types of phage infections: lytic, to directly invade bacteria – and lysogenic, to genetically integrate into the bacterial hose and slowly replicate.

While phages are a very promising alternative to antibiotics, there’s still much more research to be done to understand them. Phages are known as strong defenders, so phage therapy would be most effective with a well-differentiated group of phages that can counter the increasingly multi-resistant bacteria. In other words, phages must be very diverse to most effectively infect bacteria.

I read an interesting article by NexaBiome that discussed several research studies that were conducted on phage therapy. An excerpt from the article:

A 2022 systematic review of observational clinical data from 52 studies looking at the safety of phage therapy reported it as “well tolerated and safe.” ⁽¹⁾ Meanwhile, in 2020, another review shared that phage therapy has a long and proven history in the treatment of bone and joint infections, applied in both ‘cocktail’ and ‘personalised’ formulations ⁽²⁾.

NexaBiome

Not only that, but the article also talks about a well-known case involving a 68-year-old diabetic patient who was infected by a bacterium that was resistant to several antibiotics and treatments. 9 phages were used from a collection of phages to administer to the patient, and they helped clear the infection. Phage therapy had helped to successfully treat the patient’s condition.

There’s a lot of research out there on phages that show it as being a potential successor to antibiotics, and while there’s a lot of research to be done, there’s definitely reason to be optimistic that there will one day be a treatment that can successfully combat bacterial infections without resistance. After all, phages were first discovered way back in 1915, and were learned to have the potential to kill bacteria in 1917. After more than 100 years, phages continue to show promise, and with advancing technology, research will only continue to accelerate in learning more about them.