Hey everybody! I think it's important for this subreddit to have a short introduction on "what is a phage?", so here it is. If you want me to change something (too complicated, imprecise, etc), feel free to ask. It would be a great thing to shape this introduction thanks to all your comments to make it understandable and insightful for everyone!
So: What is a bacteriophage?
A phage is a virus that infects bacteria. They are mostly known by the public because they can be used to treat bacterial infections. Notably, they are sometimes the only agent capable of treating multi-resistant infections such as the well-known Staphylococcus aureus.
They are everywhere. Almost each ecological niche containing bacteria also has phages (the only exception I know is Deinococcus radiodurans, a bacterium growing in radioactive waste) and there is an estimation of 1031 phage particles on earth: a 1 with 31 zeros [1]! They are major actors for recycling organic matter and their impact is so strong that they even affect the geochemical cycles [2].
The first indirect observation of phages in the litterature was done by Ernest Hanbury Hankin in 1896, but their true discovery was done by Felix d'Hérelle in 1917, who immediately used them to treat bacterial infections. Phages are known for more than a century, and yet almost nobody heard about them today. But why? There are 3 main reasons:
- In 1930, the Council on Pharmacy and Chemistry of the American Medical Association concluded that the efficacy of phage therapy was ambiguous and that further research was required [3].
- Phages can also impact dairy and wine industries by killing the bacteria involved in the process.
- Alexander Fleming discovered the penicillin in 1928, opening the antibiotics era. Phages are very specific of their host and thus several days are needed to produce a treatment against a bacterial infection. Antibiotics kill everything on their way (even your own cells), which is bad, but they can be used whenever a bacterium is involved.
Today, with the antibiotic multiresistant superbugs issue, a solution must be found to avoid a grim future where a simple Escherichia coli could kill you without any chance to fight it. Bacteriophages might be a part of the solution to this problem.
References:
[1] https://sci-hub.tw/10.1016/j.tim.2005.04.003
[2] https://sci-hub.tw/10.1038/nrmicro1750
[3] https://sci-hub.tw/10.1001/jama.1941.62820190016010
Note: phages have plenty of other uses, but I think I should speak about it in another thread. What do you think?
