A phage-based diagnostic identifies bacterial infection by detecting the live pathogen in a blood sample.
The phage is the natural enemy of the bacteria and is highly specific, so it only infects a particular stain of bacteria.
Mycobacteria Tuberculosis (Mtb) is the bacteria that causes tuberculosis (TB). Actiphage takes advantage of this specificity of interaction between a phage and its host bacteria to create a rapid diagnostic for TB and other diseases caused by mycobacteria.
When Actiphage finds live mycobacteria within a sample of blood or milk, it penetrates the bacteria, and replicates rapidly within it. As the volume inside the bacteria increases, eventually its tough cell walls will rupture, releasing the bacterial DNA (lysing the bacteria) for identification with qPCR.
The benefits of phage-based diagnostics are significant:
Identifies live infection at an early stage - as the phage only replicates in live cells it is able to detect its host bacteria at very low levels in the blood (bacteraemia), before the infected person or animal begins to generate an immune response.
Rapid diagnostic - the bacterial DNA is released within hours to enable rapid identification with qPCR.
Identifies the genotype of the mycobacteria - There are many different strains of mycobacteria, and some genotypes are more virulent than others. With a phage-based companion diagnostic it would be possible to provide personalised medicine, matching the drug to the strain.
Provides screening of high risk populations - children infected with Mtb, especially those malnourished or stressed, have a higher chance of progression to TB disease. TB disease is preventable but early detection in children is difficult as many are unable to produce sputum for analysis. Screening with Actiphage requires a blood sample, instead of sputum, and these types of sample are easier to collect in the community.
