You all know how much I love cool science by now – and how much hope I have for using bacteriophages to positively alter the bacterial microbiome. I’m excited then to report to you super cool science leading to major progress on the phage front.
For those new to the term bacteriophages: these are viruses that kill bacteria. They are specific to one kind of bacteria, like a key fitting into a lock, and for a hundred years have been recognized as a potential way to treat bacterial infections. Unfortunately, once antibiotics were developed, interest in phages waned along with research into them. I wrote a post on the history of phage therapy last year– see here. Anyway, with the ever increasing issue of antibiotic resistance around the world, phage therapy has come back into fashion and I see an increasing number of articles appearing in the last couple of years.
Today’s research is out of the UK: scientists at the Institute of Food Research in the town of Colney – near Norwich – have discovered a completely new bacteriophage which looks very promising for treating Clostridium difficile, which is a horrific bacterial infection of the gut that is very hard to treat, and recurs with great frequency. C.diff causes potentially deadly diarrhea: according to the CDC, almost half a million people in America alone are infected each year, and approximately 29,000 of those people die within a month of contracting the infection.[i] It is commonly contracted during a course of antibiotics and, ironically, is treated with more antibiotics, leading to greater and greater antibiotic resistance: “Clostridium difficile infection is increasing in both frequency and severity, with the emergence of new highly virulent strains highlighting the need for more rapid and effective methods of control.”[ii]
These scientists 27 different strains of C.diff looking for phages that are the natural enemy of the bacteria, and found one they named ΦCD27 (phiCD27) – a completely new, never-before-isolated – kind of bacteriophage. It has been named after the town in which it was discovered: Colneyvirus. Since it was first isolated, 4 other species of Colneyvirus have been identified, and now is considered an official genus of virus unto itself.
News Medical Net has an interesting summary of the research in which they explain how phages work: they “…exist and reproduce by injecting their genetic material into bacteria, and using the host’s own machinery to construct new viruses inside the cell. They then release enzymes called endolysins that destroy the bacterial cell wall, releasing the new viruses.”[iii] In this case, the researchers found the gene for ΦCD27’s endolysin, and went on to produce the enzyme. They found it was active against 30 different strains of C.diff, including the most virulent strains, while not bothering other species of bacteria in the slightest.
Obviously, more work needs to be done first, but this is certainly one of the most promising bits of research I’ve seen in a long time on this front: “In contrast to conventional antibiotic treatments, treatment with the CD27L C. difficile endolysin, with its exquisite specificity, offers a novel approach to the destruction of the pathogen with the maintenance of an effective GI tract microbiota.”
[ii] Mayer, M. J., et al. (2021) Molecular Characterization of a Clostridium difficile Bacteriophage and Its Cloned Biologically Active Endolysin. Journal of Bacteriology. doi.org/10.1128/JB.00686-08.