It is estimated that, by 2050, antimicrobial resistance (AMR) will kill 10 million people annually, more than cancer, and at a cumulative global cost of US$100 trillion. Bacteriophages ("phages") in the pre-antibiotic era were widely used as treatments for bacterial infection, and have been generally regarded as effective and extremely safe. With the looming AMR crisis, there is resurgent interest in using phages to treat bacterial infections. There are many clinical infection settings in which phages have potential as a treatment. Some of these which will be discussed are listed below.
- Chronic rhinosinusitis (CRS), which afflicts about 15% of people, and is often caused by Staphylococcus aureus. Direct introduction of phages into the sinuses could be a treatment option for this condition. Our experiences using phages to resolve S. aureus CRS in a sheep model, and in a phase I clinical trial, will be reported.
- Diabetic foot ulcers: these are a common complication of diabetes, and with the high prevalence of AMR bacteria, there is often failure to heal, leading to foot amputation. This has a 5 year mortality rate exceeding 70%, greater than that of many malignancies. Phages, especially if immobilized onto dressings, could be useful here. Again, S. aureus is a frequent cause. We have preliminary data supporting phage use in this setting.
- Blood-borne bacterial infections. S. aureus bacteremia is accompanied by a high 30-day death rate of ca. 30%.
A previously identified limitation of phages is their need to be matched with the serotype of the infecting pathogen. Our data shows that this issue is to a large extent overcome by use of phage cocktails.