Phages vs. Antibiotics

When you think about viruses and bacteria, maybe you think about being sick in bed. But did you know that there are certain viruses that can infect and kill bacteria? These viruses are called bacteriophages. For short, they are often called phages. 

Bacteriophages were discovered by two different scientists working independently of each other. Frederick W. Twort discovered them in Great Britain in 1915, and Canadian Félix d’Hérelle discovered them in France in 1917. These scientists also discovered the possibility of phage therapy. This is the use of phages to treat bacterial infections. However, when scientists discovered antibiotics in 1928, phage therapy research slowed down. This happened because antibiotics were easier to use.

But does that mean antibiotics are more effective than phages? Well, it depends. Let’s look at this debate in more detail.

Did you know? 

In 1917, Canadian scientist Félix d’Hérelle successfully treated dysentery with a virus preparation. This was before the era of antibiotics.

How do bacteriophages work? 

Bacteriophages are microscopic particles with a head and tail. The head contains viral nucleic acid. Some phages have tails and some have tail fibres.

Bacteriophages attach to bacteria using their tail or tail fibres (A). Then, they inject their nucleic acid into the bacterial cell (B). There, the virus multiplies (C, D). Finally, the newly-produced virus would burst (kill) the bacterial cell (E).This would release the virus into its host’s environment.

Did you know? 

In 1896, scientists noticed that water in the Ganges and Jumma rivers in India could kill the bacteria that causes cholera. However, no one knew how. Later, researchers began to suspect that the rivers contained bacteriophages. 

The Superbug Problem 

Some bacteria, called superbugs, are resistant to antibiotics. Patients infected with superbugs are hard to treat with antibiotics. But for any bacterial species, you can find a phage in nature that can kill it.

What happens when bacteria become resistant to antibiotics? Pharmaceutical companies have to invest in finding other ways to kill that bacteria. That costs money! Finding a phage to kill a bacterial species is cheaper and easier.

Microorganisms can change or evolve very quickly. That means bacteria are capable of evolving to protect themselves from antibiotics and phage attacks. However, viruses can also evolve. That means they can potentially produce more varieties of phages. They can potentially evolve to produce phages that can even kill superbugs! That’s another advantage of phage therapy.

Why won’t my doctor give me a phage?

Have you ever gone to a doctor for an infected wound? How about for a serious infection like pneumonia? Your doctor probably prescribed an antibiotic, not a phage. So why aren’t phages used to treat bacterial infections as commonly as antibiotics are?
There are a few reasons. One major reason is the narrow host range. A host range is the number of bacterial species a phage can kill. Usually, one specific bacteriophage only infects and kills one specific species of bacteria. For example, Streptococcus pneumoniae is a bacterium causing pneumonia. Campylobacter jejuni is a bacterium causing stomach flu. A phage that can infect and kill Streptococcus pneumoniae cannot infect and kill Campylobacter jejuni.

Let’s take the example of bacterial pneumonia. It can be caused by several species of bacteria. Two of them are Streptococcus pneumoniae and Haemophilus influenzae. Generally, both infections can be treated with an antibiotic called amoxicillin. Let’s imagine that your doctor diagnosed you with pneumonia. However, they weren’t sure which species was causing it. They could give you amoxicillin, and you would probably start to feel better. 

However, let’s imagine that your doctor wanted to use phage therapy. First, they would have to order a laboratory test to identify which bacteria had caused your pneumonia. That’s because a phage capable of killing Streptococcus might not necessarily kill Haemophilus.

So when a doctor is not sure about which bacteria is causing a disease, they will probably prescribe antibiotics. Antibiotics have a wide host range. Also, antibiotic treatment takes less time than running lab tests and then prescribing a phage. But when it comes to infections with superbugs, known antibiotics are ineffective. In these cases, phage therapy might be a better option. 

Is anyone using phage therapy?

Phage therapy has not yet eliminated the need for antibiotic treatments. But there are many reports of doctors successfully treating superbug-infected patients with phages. The Eliava Institute in Georgia is one of the first institutes to use phage therapy. There, phage therapy has successfully treated patients with skin ulcers, infected burn wounds, stomach bugs, eye infections, respiratory infections and more. These infections tend to be hard to treat. Doctors often use bacteriophages in combination with antibiotics. That’s because a wound can contain multiple pathogens. It is difficult to quickly select a bacteriophage for each one.

Did you know? 

Scientists are also researching ways to use phages to prevent and treat diseases in cattle. They are also researching using phages as disinfectants in dairy facilities.

So who knows? Maybe someday in the future, you’ll have a bacterial infection and visit your doctor. And instead of a bottle of antibiotics, you just might get a vial containing a phage!