What are the prospects for using bacteriophages to treat mycobacterial infections?
Here are some further details.
Mycobacterial infections come in many variations and levels of severity, including tuberculosis and non tuberculous mycobacteria (NTM) infections of Cystic Fibrosis patients. Tuberculosis is caused by infection with Mycobacterium tuberculosis, and many infections are sensitive to antibiotics and can be treated well, although an extensive course of several different antibiotics is required. However, many infections involve variants of M. tuberculosis that are resistant one, several, or nearly all available antibiotics.
The prospects for beneficial use of bacteriophages to treat TB are uncertain. There are two potential types of utility: 1) treatment of multi- and extensively-resistant M. tuberculosis infections, and 2) in combination with antibiotics with a view to shortening current treatment regimens and to reduce the incidence of antibiotic resistance. Although there are some studies to test phages against TB in mice many years ago, there have been no clinical trials in humans. The pathology of TB is complex, and there are many questions about whether phages will have access to intracellular bacteria and those with granulomas. There are also prospects for using phages to prophylactically prevent acquisition of TB, but this also remains untested.
Although there is little information on whether phages might be useful for treating NTM infections, there is one case study in which a cocktail of three phages has been successfully used to treat a highly antibiotic resistant infection of M. abscessus, a common NTM strains associated with Cystic Fibrosis. This study suggests a plausible solution to treating such infections. However, it is important to recognize that in this case, prior to treatment it was demonstrated that the phages in the cocktail efficiently infect and kill the specific strain of M. abscessus.
Unfortunately, different patients are typically infected with different strains of bacteria, even though the bacteria may all belong to the same species (e.g. Mycobacterium abscessus). And these different strains have different and distinct sensitivities to different bacteriophages. Thus, phages that might work successfully for one patient are usually not useful for other patients. So the successful treatment with one patient is not a universal solution to these types of infections.
Because of this strain variability, any prospects for therapeutic phage intervention for NTM infections requires isolation and growth of the specific bacterial strain and testing to see what if any phages it is sensitive to. In some cases, phages can be engineered for more effective use. However, the screening is not quick and in our experience finding a good group of phages is rare. At least until the time when we have a better understanding of the biology and he genetics of these systems.
If I have a drug resistant infection of M. abscessus, are there phages to help me?
As noted above, any particular strain associated with a mycobacterial infection needs to be evaluated for whether phages could be useful. We have only a limited ability to test individual strains, and it is relatively slow. Even if successful, there is considerable paperwork needed to establish authorization for treatment. Our experience is solely within the research arena. We do not have clinical expertise and rely in clinically-trained collaborators for such endeavors.
We are willing to receive inquiries from physicans, but we do not have the capacity to test large numbers of strains. sorry, but we are not able to respond to inquiries from individual patients.