'I'm not fat, it's viral' - Phage found in gut bacteria may aid obesity

By Dan Stanton

- Last updated on GMT

New bacteriophage discovered in gut bacteria could be a key factor in obesity
New bacteriophage discovered in gut bacteria could be a key factor in obesity

Related tags Bacteria

A newly discovered virus which infects intestinal bacteria might be a cause of obesity, but could increasing interest in bacteriophages drive new personalised medicines and alternatives to antibiotics?

For those of you who have put on a few pounds of late, it may not be the lack of exercise, fast-food culture or sugar-filled sodas driving the rise in obesity but a virus which could be in half the world’s population and infects common types of gut bacteria.

The bacteriophage (phage) – a virus that infects and replicates within a bacterium – was discovered by a team of researchers at San Diego State University (SDSU) who last week published its findings in the journal Nature Communications​.

Named crAssphage, the phage infects Bacteroidetes which live towards the end of the intestinal tract, and after discovering it accidentally, lead virologist Robert Edwards told Biopharma-Reporter.com his team will now investigate what implications such interactions may have.

“The next steps are to isolate this virus in the lab, which has been particularly tricky to accomplish, and then investigate its interactions with its host in the laboratory,” he said. “This will give us the framework that we need to build up for future studies.”

Phages work just like other viruses, injecting their DNA into targeted cells and hijacking the cell's machinery to replicate themselves before killing off the cell as they escape back into the environment to find another host.

However, “we know very little about the way that phages and bacteria interact with each other in our intestines, and how this could contribute to health or disease,” Edwards said. ​One area he is looking into is personalized phage medicine, where phages are extracted from patients, modified and replaced.

Late-Phage Discovery

Next year marks the hundredth anniversary of the first discovery of phages but according to Michael Jarvis, Reader in Immunology & Virology at the University of Plymouth “we are assuredly only touching the surface in terms of the number of identified viruses.

Historically, viruses were only identified if they caused clinical disease (at least in animals), or lysis of bacteria (if you're a phage),” ​he told this publication.  “A good example of the former situation is HIV, which may still be unknown today except for that it caused overt immunosuppression and death.”

However, Jarvis suggested the rate of virus discovery is increasing due to next generation sequencing technology which detects viruses blindly based only on homology of identified sequence data in a source sample.

Alternatives to Anti-biotics?

Increased discovery is stimulating commercial interest, with pharma currently interested in ‘phage therapy.’ “The goal is to capture wild phages and use them to kill bacteria as an alternative to antibiotics,” ​Edwards told us, combating the problem of antibiotic resistance.

These live therapies self-propagate and kill their target, yet Phages also adapt to new bacterial resistance form and combat infections where antibiotics fail.

Jarvis mirrored Edwards’ views, adding “phages were investigated in the early 1900s as possible anti-bacterial agents and [the problem of antibiotic resistance] may have raised interest again.”

Historically, at least five phages were commercially produced by the French company which became cosmetics firm L'Oréal, whilst Eli Lilly produced seven phage products for human use in the 1940s.

However, the West abandoned much of its research in favour of anti-biotics, though phage therapy continued in Eastern Europe and Soviet countries, according to an article in the journal Antimicrob Agents Chemother​.

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