Before the discovery of antibiotics in the 1930’s, there was an effort to treat bacterial infections using bacteriophages. Bacteriophages are viruses that infect bacteria, and they occur naturally wherever bacteria are found, from lakes and streams to the microbiomes inside our bodies. The enormous benefit of bacteriophages is, ironically, what led to their disuse in favour of antibiotics: they only target specific bacteria. Because it’s difficult to know exactly which bacteriophage or set of bacteriophages should be used to target a specific infection, they can be hard to use. Especially in the 1930’s, before we had as deep an understanding of genetics as we do now, administering the right bacteriophages to cure a particular infection was tricky.

Antibiotics, which inhibit growth in a range of bacteria, were easier to deploy at the time and led to better patient outcomes. Naturally, most medical systems switched mostly or entirely to treatment regimens using antibiotics for bacterial infections, and research into phage therapy slowed. The invention of antibiotics is certainly one of the most important medical discoveries in the past hundred years, but we are beginning to find challenges with their continued use.
For one thing, new research has begun to show that the composition of our own various microbiomes – especially in the gut – can have an impact on our health. Exposure to antibiotics (especially in youth, as outlined in a February 2024 paper in The Lancet) can affect our gut microbiome and possibly lead to adverse health outcomes.
Multi-drug resistant infections are on the rise, and we desperately need new solutions to treat infections.
More immediately, the threat of antimicrobial resistance (AMR) makes finding novel treatments for bacterial infections a high priority globally. According to the WHO, AMR was directly responsible for 1.27 million deaths in 2019 alone, and was a contributing factor in 4.95 million. The pipeline for new antimicrobials has been largely stalled in recent years, meaning that bacteria have had time to catch up. Multi-drug resistant infections are on the rise, and we desperately need new solutions to treat infections.
Late last year, a group of researchers from institutions across France published a paper on training artificial intelligence to pick the most appropriate bacteriophage or set of bacteriophages to treat an infection based on a genetic sequencing of the infecting organism. In 90% of cases, the selected bacteriophages successfully destroyed the bacteria. The researchers chose to focus on Escherichia coli for their work, but the approach could be applied to other organisms as well. They intend to test the approach in a variety of other environments and to train their AI model to work with other bacteria as well.
The WHO has been leading a dialogue around the use of phage therapy to treat antimicrobial resistant infections, in collaboration with the Global Antimicrobial Resistance Research and Development Hub. Some clinics already perform phage therapy, such as the Eliava Phage Therapy Center, based in Georgia. A WHO article from last year listed several cases of people with chronic, multi-drug resistant infections who were able to recover fully after receiving phage therapy.