The Post-Antibiotic World: Phage Therapy

Source: Russel Kightley

Antibiotics have been humanity’s go-to treatment for infectious disease for the best part of the last 100 years, ever since Alexander Fleming famously discovered penicillin in mouldy bread (penicillin was actually discovered 30 years before this, but that’s a story for another time). However, in the modern world, many diseases, such as tuberculosis, are starting to show resistance to the antibiotics we use to treat them. Many suggest that we need new solutions for tackling infectious disease and that we need to be fully prepared for the post-antibiotic world.

First off, a quick crash course on what antibiotics are, why antibiotic resistance occurs, and why it’s a massive problem.

For the purpose of this article, pathogens are microorganisms that infect us, and antibiotics are the chemical compounds we use to specifically kill them, without harming our own cells.

Almost all pathogens have different DNA sequences. This means that they will not behave exactly the same and will be affected differently by different chemicals. For example, some will be less affected by antibiotics. Furthermore, a few pathogens will be naturally resistant to antibiotics. When we use antibiotics on a population containing these individuals, we kill every pathogen but these resistant microorganisms. They quickly replicate, filling the space left by the others, and you’ve suddenly got yourself a whole population of pathogens resistant to your antibiotic.

Aided by a growing population increasingly taking unneeded antibiotics, or not finishing antibiotic prescriptions (always always ALWAYS finish your prescriptions), pathogens such as the tuberculosis bacterium have developed resistance to almost every family of antibiotics. They’re also developing resistance faster than we can design new antibiotics, with 480,000 new strains of multi-drug resistant cases of tuberculosis reported last year across the globe.

In this article, we’ll look at phage therapy. This utilises the family of viruses evolved to infect and kill bacteria: bacteriophages. This sounds counterintuitive; infecting yourself with a virus to eliminate the bacteria already infecting you, like eliminating a hangover by taking a shot of vodka. However, these bacteriophages are actually incredibly specific. Not only are they completely incapable of infecting humans, they hit just one species of bacteria. This incredible specificity means that resistance appears more slowly, as the general bacterial population is less exposed to and affected by the treatment.

It’s pretty well developed, too. In fact, it’s been around for about as long as antibiotic treatment. So why have you or I never been treated with a phage?

The answer is politics. Back in the mid-20th century, stuck behind the iron curtain, countries in the Soviet Bloc didn’t have access to the latest western antibiotics. To make do, they began developing phage therapy. To this day, phage therapy is pretty common in countries such as Russia, Georgia, and Poland.

Now that antibiotics are running into problems, some scientists believe that phage therapy could be an answer to their prayers. Not a replacement for antibiotics, but an effective enough partner to keep pathogens in check. As of now, the EU is investing $5.2million in a massive clinical trial of phage therapy, fantastically named ‘Phagoburn’. In 50 years, we may regard phage therapy to be the best thing to come out of the Soviet Union, besides imposing statues and masculine facial hair.

On the cutting edge of phage therapy design, researchers at MIT were able to create a modified phage which only targets antibiotic resistant bacteria. This is far cleverer than it first appears: in one fell swoop, it lessens its own resistance pressure on the general bacterial population, whilst making that very same general population more susceptible to conventional antibiotics. This essentially traps the pathogen between a rock and a hard place: the more it evolves in one direction, the more it will be beaten back to a treatable form.

From an industrial standpoint, there are some problems. After a 2013 United Nations hearing, it is now illegal to patent whole genomes or viruses. This lessens drug companies’ interest, as they are reliant on patents for a large amount of their income. However, more developed and engineered viruses, such as the example mentioned above, may be sufficient to fly under the radar and be patented, increasing corporations’ motivation to create effective treatments.

In my first year as a molecular biology student, I was taught an important concept. No matter how effective your treatment is, regardless of how many plans against resistance you make, as long as 0.0000000001% of a population survives, resistance will always develop. It might take decades, but it is all but impossible to prevent altogether. The war on pathogenic resistance will likely never end, but it seems equally likely that phage therapy, amongst other techniques, will give us the weapons to survive, for now.

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