Isolating Bacteriophage for the treatment of the enteric pig pathogen Salmonella
Research partners: University of Leicester
Sponsors: AHDB Pork
Project duration: 2015-ongoing
Aims and objectives
To isolate a set of natural viruses known as bacteriophages that specifically infect the common Salmonella serotypes associated with pigs. To characterise the bacteriophages and select those that have properties that facilitate their future development use as an alternative to antibiotics to treat Salmonella infection in pigs.
The goal of this study was to investigate whether it would be feasible to use bacteriophages to treat Salmonella infection in pigs. Not only would this give the industry an alternative to the traditional antibiotic treatment, but as bacteriophages are specific to bacterial species they could also be developed as a diagnostic tool to be used to identify Salmonella infection on pig farms.
Findings to date
A panel of 21 bacteriophages (Figure 1) have been isolated from pig faecal samples collected from UK farms and surrounding areas. These are able to lyse the top Salmonella sub-groups associated from pigs in the UK, including 95% of multi-antibiotic resistant Salmonella strains isolated from outbreaks in farms (collected by the Animal Plant and Health Agency) from dominant UK Salmonella serotypes: S. Typhimurium, 4,12:i:-, 4,5,12:i:-, S. Bovismorbificans and S. Derby.
The bacteriophages have been fully sequenced and no virulence genes are present suggesting they can be used therapeutically. Further characterisation of the phages identified two exceptional bacteriophages and when combined could lyse Salmonella by 4-logs in 2 hours. In addition they are stable at temperatures up to 70°C and be converted from liquid to powder by spray drying.
For delivery of bacteriophages to pigs the next stage of the project is to test if combining bacteriophages to pig feed would be feasible and if bacteriophages remain active following the feed manufacturing process. Followed by testing the efficacy of phage-feed in Salmonella pig models.
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