By Kruti Bhargav
I’m sure in the past when we’ve gotten sick, we’ve all gone to the doctor, taken the medicine or antibiotics they prescribe, and then gotten better. Well, have you ever heard of viruses taken into the body when you are sick, instead of antibiotics, to kill the bacteria? That's essentially what phage therapy is! Phage therapy, also known as viral phage therapy, is the therapeutic use of bacteriophages to fight against pathogenic bacteria. Bacteriophages are a type of virus that infect bacteria, use them as hosts, and ultimately kill them. In this age of multidrug resistant bacteria, phage therapy may be the miracle alternative to antibiotics.
How do phages and phage therapy work?
Most bacteriophages kill bacteria by causing them to burst. When a phage attacks a bacteria, it binds to it and injects its genetic material into the bacteria. Following infection, the bacteriophage hijacks the bacterium's cellular components to prevent it from multiplying, and uses the bacteria as a host cell to produce viral components. The phage multiplies inside the bacteria, and eventually causes it to break open, releasing new phages into the system, a process known as lysis. The phages continue multiplying and killing all the bacteria until there are none left in the body. As the bacteriophages are specific and only attack one certain kind of bacteria, they remain dormant without harming any other cells, such as our body cells, until they come in contact with the same specific bacteria again.
A group of phages, in green, attacking an E. coli cell, injecting their DNA through the cell membrane
(Source: The New Yorker)
Phage Therapy vs. Antibiotics
Currently, most of the bacterial infections or illnesses that we encounter are cured using antibiotics (A common example is Penicillin). However, most antibiotics are not specific, which means that they don’t only attack the harmful bacteria; they also kill the beneficial ones that our body requires. Furthermore, the use of antibiotics can lead to antibiotic resistance in the bacteria. I’m sure we’ve all heard our doctors advise us to complete the entire antibiotic treatment and not stop in the middle. Well, this is because an incomplete treatment could lead to antibiotic resistance in the bacteria. Antibiotic resistance occurs when a bacteria contains a gene that makes it resistant to an antibiotic, which means it can’t be killed with that antibiotic. This bacteria then survives, while all the other non-resistant ones die. This resistant bacteria then reproduces, forming more resistant bacteria. This then leads to a continued bacterial infection which now cannot be cured with the antibiotic, as all the bacteria are resistant.
Antibiotic resistance has become an extremely common issue, with certain bacteria being resistant to multiple different types. This has led to major problems in the medical industry today, as most antibiotics are ineffective in fighting bacterial infections. Therefore, alternate methods must be found to help combat this issue. Bacteriophages have always existed in nature, but harnessing their power as a way to fight bacterial infections has been a recent development, and one that has proven to be successful.
A British girl with cystic fibrosis received a lung transplant, which allowed a chronic Mycobacterium abscessus infection to develop. The infection became life-threatening, affecting her liver and lungs. Unable to cure the girl after multiple attempts with more than 20 different commonly used antibiotics, the doctors turned towards the wide range of bacteriophages at the Department of Biological Sciences at the University of Pittsburgh. Three types of bacteriophages that could infect Mycobacterium abscessus were identified and genetically modified to improve their ability to kill the bacteria. As phages are specific and only attack certain bacteria, our normal human cells are in no danger. After days of continuous supply of the phage into the girl’s blood stream, there was a decline in the amount of M. abscessus bacteria, saving the girl’s life.
Bacteriophages attacking a bacteria
(Source: Pharmaceutical Technology)
With an increase in antibiotic resistance and a decrease in the number of antibiotic options, it comes down to identifying new and unique ways of fighting against harmful bacteria. Of course phage therapy is just one of the ways in which this can be done, and many more are yet to be discovered. Currently, there is still research being conducted into the potential safety risks and uses of phages, but there is still a long way to go before our doctors prescribe phages instead of antibiotics for infections. However, while something that we cannot see threatens our lives, sometimes, the solution to a problem may already be around us, just like the bacteriophages!
Twilley, N. (2015, February 6). Inside the World of Viral Dark Matter. Retrieved September 05, 2020, from https://www.newyorker.com/tech/annals-of-technology/phage-killer-viral-dark-matter
Vaidya, A. (2019, October 17). 10 most common antibiotics administered in the ER: Ceftriaxone and azithromycin are the top two most commonly administered antibiotics in U.S. emergency rooms for patients who are not admitted to the hospital, according to a study published in the American Journal of Health-System Pharmacy. Retrieved September 04, 2020, from https://www.beckershospitalreview.com/quality/10-most-common-antibiotics-administered-in-the-er.html
Bacteriophage therapy: Phage therapy is saving lives against superbugs. (2019, May 14). Retrieved September 05, 2020, from https://www.pharmaceutical-technology.com/comment/bacteriophage-therapy/