Phage-based diagnostics identify bacterial infections by detecting live pathogens circulating in the blood.
A phage is a virus-like particle that is specific to a particular stain of bacteria, such as Mycobacteria Tuberculosis (Mtb) that causes tuberculosis (TB). Actiphage takes advantage of the specificity of interaction between a phage and its host bacteria to create a rapid diagnostic for TB and other diseases caused by mycobacteria.
The phage is used to find live mycobacteria; it penetrates the bacteria, replicating rapidly within it. As the volume inside increases, eventually the tough cell walls will rupture, releasing the bacterial DNA (lysing the bacteria).
The DNA is then available for identification with qPCR.
Identifies live infection at an early stage - the phage only replicates in live cells and 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 Actiphage as a companion diagnostic it would be possible to provide personalised medicine, matching the drug to the strain.
Provides screening of high risk populations - children, those with HIV or diabetes and those malnourished or stressed are more likely to develop TB disease but also find it difficult to produce sputum for analysis. Actiphage is a blood test that can be produces samples that are easy to handle in the community.
The results from initial trials are very promising.