Most people have heard about the importance of the gut microbiome. That usually means the range of bacteria found primarily in the large intestines. However, we also host a large number of viruses along with the bacteria. A few years ago, a study from Japan examined the relationship between bacteriophage viruses in the gut microbiome and autoimmune diseases.
What Is a Bacteriophage?
Have you ever heard the expression the enemy of my enemy is my friend? That could well be true in our body. Over the last decade, scientists have discovered that the gut microbiome is extremely important to human health. When people think of the collection of germs that live in the digestive tract, they normally focus on bacteria. But there are also bacteriophage viruses. They help maintain balance in your GI tract.
You know the word bacteria. These microorganisms are everywhere including in and on our bodies. You have heard of Escherichia coli (E. coli), Clostridium difficile (C. diff) and Staphylococcus aureus (S. aureus). Such germs can be bad actors.
A “phage” is a virus that “eats” bacteria. More precisely, bacteriophage viruses infect bacteria, replicate themselves, destroy the germs and move on to invade and “devour” other similar bacteria.
Bacteriophage viruses are very different from antibiotics, which are often “broad spectrum.” That means they kill off a bunch of different kinds of germs, both good ones as well as bad ones. Think of these drugs like big bombs that are not very discriminating.
Phages are very specific for particular bacteria. Think of them a bit like smart bombs that go after only one bacterial target. That makes them far less destructive to the good guys.
Bacteriophage Viruses are the Enemies of our Enemies:
Did you know that the most common biological entities on our planet are bacteriophages? They are everywhere—in the ocean, in the dirt, and in our bodies.
A study published in the journal Cell (Feb. 18, 2021) reports on more than 140,000 viral species in the colon. Most had not been previously characterized. Many bacteriophage viruses help keep bacteria under control. Phages might serve to maintain harmony within the digestive tract.
The authors of this groundbreaking study introduce their research this way:
“The impact of phages on different ecosystems is beginning to be uncovered, with phages found in the oceans already being referred to as ‘puppet masters’ due to their significant impact on oceanic biogeochemistry. Given the impact of the gut microbiome composition and function on human health, there is a growing focus on phages that inhabit the gut ecosystem.”
Mapping the Ecology of our GI Tracts:
The investigators have created the Gut Phage Database (GPD). To do so, they analyzed human samples and uncovered a diversity of bacteriophage viruses that is truly mind boggling.
This is revolutionary research. It may help clinicians better understand imbalances in our gut microbiome that could contribute to conditions like inflammatory bowel disease.
How Do Phages Attack Bacteria?
Scientists have long wondered just how phages work to overcome bacterial infections. A study in Science reveals how a phage dubbed PP7 infects Pseudomonas aeruginosa, a type of bacteria that can cause serious infections (Science, April 5, 2024). The phage targets a cylindrical extension from the surface of the bacteria called a pilus. P. aeruginosa relies on its pili to form biofilms and infect host cells. Where the phage attaches, the pilus retracts into the cell, admits the phage and snaps off. The scientists believe this will help address the problem of multi-drug resistant bacteria.
They concluded:
“This work could serve as a benchmark for investigating other phage and virus systems of different organisms.”
What Is the Connection with Autoimmune Diseases?
Japanese researchers found that lower diversity of bacteriophages was associated with more rheumatoid arthritis and lupus (Annals of the Rheumatic Diseases, Feb. 2022). They examined the abundance of crAss-like bacteriophage viruses. People with these autoimmune conditions had far fewer of them. According to the scientists, phages are homing in particularly on bacteria such as Faecalibacterium and Ruminococcus.
Previously, scientists had found that the viruses in our guts are diverse, stable and highly individual (Cell, Host & Microbe, Oct. 9, 2019). Presumably, the bacteriophage viruses also reflect diversity and stability of the bacteria that make up so much of our gut ecology.
Using BacteriophageViruses Against Diseases:
One of the most compelling interviews we conducted in the last few years was about phage therapy. Dr. Steffanie Strathdee helped saved her husband’s life by tracking down bacteriophages that could fight off a deadly bacterial infection. Later, the couple wrote a book titled The Perfect Predator: A Scientist’s Race to Save Her Husband from a Deadly Superbug: A Memoir.
You can listen to this amazing story at this link. (Show 1155: Can Bacteriophages Save Your Life?) Download the free mp3 file or listen to the streaming audio by clicking on the arrow inside the green circle under Dr. Strathdee’s photo.
If you would like to learn more about your own microbiome, you may want to check out the website of one of our former sponsors, Verisana. This German company provides home health tests for gut health and the microbiome. Here is a link to learn more.
