Phage therapy is a medical approach that uses naturally occurring viruses, called bacteriophages, to treat bacterial infections. This strategy offers a targeted way to combat bacterial pathogens, particularly those that have developed resistance to conventional antibiotics. It provides an alternative or complementary treatment option in the face of escalating global health challenges posed by drug-resistant bacteria.
The Role of Bacteriophages
Bacteriophages, or phages, are viruses that specifically infect and destroy bacteria. These biological entities are among the most abundant and diverse on Earth, found in various environments such as soil, water, and even within the human gut. They exist in immense numbers, far exceeding bacterial populations. A typical bacteriophage consists of genetic material, which can be DNA or RNA, encased within a protein shell called a capsid, often with a tail structure that aids in infection. Phages are highly specific, targeting only bacterial cells and leaving human cells unaffected.
How Phage Therapy Works
Phage therapy operates through the lytic cycle, where bacteriophages attach to and destroy bacterial cells. The cycle begins when a phage attaches to specific receptors on the surface of a bacterial cell. It then injects its genetic material into the bacterium, essentially hijacking the host cell’s machinery.
The bacterial cell is then reprogrammed to produce new phage components, including genetic material and proteins, instead of its own cellular components. Once numerous new phage particles are assembled inside, the bacterial cell lyses, or bursts open, releasing hundreds of new phages to infect other bacteria.
Why Phage Therapy Matters
Phage therapy is gaining interest due to the increasing global crisis of antimicrobial resistance (AMR). Antibiotic-resistant infections were directly responsible for 1.27 million deaths worldwide in 2019, and contributed to nearly 5 million deaths. The continuous misuse and overuse of conventional antibiotics have led to a diminishing effectiveness of these drugs, rendering many infections difficult or impossible to treat. Phage therapy offers a potential alternative or complementary treatment, especially for multi-drug resistant infections, because its mechanism of action is distinct from antibiotics. Its high specificity means phages can target resistant bacteria without disrupting the broader microbiome, a common side effect of broad-spectrum antibiotics.
Current Use and Development
Phage therapy has a long history, particularly in Eastern Europe, where it continued to be used clinically even after antibiotics became widespread in Western medicine. Institutes in countries like Georgia and Poland have extensive experience with phage applications. In Western medicine, phage therapy is re-emerging, often used in compassionate care cases for severe infections that have not responded to conventional antibiotics. These cases have demonstrated the potential and safety of this approach, particularly for multidrug-resistant pathogens.
Ongoing research and clinical trials are exploring broader applications for phage therapy, including its potential use in combination with antibiotics. Regulatory bodies, such as the U.S. Food and Drug Administration (FDA), are engaged in establishing pathways for approval that accommodate the unique characteristics of phage products. While no specific phage approval pathway currently exists, progress is being made to integrate phage therapy more widely into modern healthcare systems, with around 90 clinical trials ongoing globally.