The role of Actiphage® as a powerful research tool for tuberculosis-related diseases is to be explored at the 15th International Association for Paratuberculosis Colloquium (ICP2022) in Dublin on 12 – 16th June 2022. Results from a study of co-infection of bison will be presented and the new Johne’s Disease Testing Service will be discussed on the Biosellal stand where PBD Biotech has a presence.
First results show Actiphage detects co-infection in bison
The poster, to be presented by Professor Cath Rees of the University of Nottingham, is the first time that Actiphage has been applied to detecting co-infection of North American bison. The nature of infection in the seven bison was unknown, so Actiphage was used as a lysing agent to extract DNA from viable mycobacterial cells, then different PCR assays were applied to identify the type of Mycobacterium causing the infection.
The robust nature of the mycobacteria means that extracting the DNA for identification by PCR is problematic and physical or chemical lysis methods are inefficient. In contrast, the phage lysis has evolved to be highly efficient and allows Actiphage to detect very low (<10) numbers of cells.
Additionally, since the assay directly detects the presence of the organism rather than an immune response, the method can be applied to any species of animal. Actiphage’s developer, PBD Biotech, has recently launched a Johne’s Disease testing service that uses Actiphage to detect Mycobacterium avium subsp. paratuberculosis (MAP) in the blood of cattle and farmed deer.
The bison study successfully identified the presence of MAP in six animals, of which two also had evidence of M. avium co-infection; in the remaining animal only M. avium was detected. This is an important finding as it shows Actiphage is a powerful tool for disease management in species where there is limited availability of immunological tests.
The results demonstrate the ability of Actiphage to successfully extract DNA even when few cells of viable Mycobacteria are present, and offers a utility for both rapid detection and sub-speciation due to it compatibility with existing PCR-based assays.
Early detection of MAP in calves
Actiphage has also been used to detect MAP in the blood of experimentally infected calves (Swift et al., 2020).
Earlier findings from a study by Biosellal and PBD Biotech found that MAP could be detected in the blood of day-old calves born from MAP-positive mothers. Previously Johne’s Disease was only reliably diagnosed in 18 – 24-month calves after they had started to shed MAP into their faeces.
The study involved monthly testing on calves from three different herds – born from MAP-positive and MAP-negative cows – using PBD Biotech’s Actiphage kit and Biosellal’s Bio-T kit® MAP PCR on blood samples. This landmark study showed that there was a window of opportunity between birth and shedding of MAP to detect and control the disease.
See us at ICP on Biosellal stand
Jonnie Yewdall, Commercial Director for PBD Biotech, will be available for discussions at the Biosellal stand at ICP. The Biosellal PCR kit is verified and validated to detect MAP and works with Actiphage.
Diagnostics and detection – Poster Pitches
Tuesday, June 14, 2022, 12:45 PM – 1:00 PM, Main Auditorium, Printworks
Detection of MAP and M. avium co-infection in North American Bison using Actiphage – Prof Cath Rees
Optimization of Actiphage for detection of MAP in different hosts, including humans – Prof Cath Rees
