Special viruses called bacteriophage infect bacteria, but they don’t always kill their target. In fact, a recent discovery uncovered bacteriophage inside of the healthy bacteria living in our gut, a population of microorganisms scientists call the microbiome.
The new discovery indicates that human gut bacteria have their own version of a microbiome, and it consists of bacteriophage that don’t cause any harm (as far as researchers can tell so far). Any instances of gut bacteriophages have been ignored until recently because scientists never saw them causing problems, and they didn’t know how to study them anyway.
However, in a recent PNAS study led by scientists from Montana State University, researchers sequenced the genes of bacteriophage from two individuals’’ microbiomes, combined their findings with genetic data from a previous study of more than 160 individuals’ gut bacteriophage genetic sequences.
They ended up identifying 23 distinct bacteriophage that seemed to be associated with a healthy gut. One-third of the participants had healthy guts while the remaining two-thirds had chronic intestinal illnesses, either Crohn’s disease or ulcerative colitis. Of the 23 beneficial bacteriophage identified, nearly all of the viruses were found in the healthy gut individuals rather than in the patients with chronic intestinal disease.
"Most virologists are looking at how viruses cause disease," said Mark Young, PhD, from Montana State University. "We're flipping that around, and looking at the possible role for viruses in promoting health."
Previous research has indicated that a diverse microbiome, meaning gut bacteria, is linked to a variety of health benefits. However, the results from the present research study show that gut bacteriophage populations are even more diverse than gut bacteria.
Overall, Young and the other study scientists believe that viruses in the gut are somehow helping to maintain human health in collaboration with gut bacteria. However, they can’t confirm that the bacteriophage are part of the cause or just a component of a healthy individual’s gut microorganisms. Scientists in the field believe that future studies need to include more participants as well as more diverse groups. Researchers believe that they should consider the impact of a person’s diet on gut viruses as well.
One theory of how gut bacteriophage benefit human health is by controlling which bacterial species thrive in the gut. Just like other types of viruses are capable of infecting and killing humans, bacteriophage can infect and kill bacteria.
In the future, should the theory pan out, researchers could use specialized bacteriophage to target dangerous bacterial species. There are still a lot of questions concerning the good viruses living in our gut bacteria, but scientists are sure to quickly launch projects to figure out all the details. You haven’t heard the last of the healthy human gut phageome.
Sources: Proceedings of the National Academy of Sciences
, Montana State University, NPR