Photo: Professor Aaron White (left) and Akosiererem Sokaribo have been working on a salmonella vaccine. (Credit: Dave Stobbe for the University of Saskatchewan)
By Federica Giannelli
With 94 million cases of gastroenteritis — “stomach bug” — every year worldwide, protecting against salmonella is more relevant than ever.
At the University of Saskatchewan, researchers have been working on a novel salmonella vaccine that holds promise for preventing this food-borne infection. The vaccine, being developed at the university’s Vaccine and Infectious Disease Organization — International Vaccine Centre (VIDO-InterVac), has shown positive preliminary results in animal models.
“As salmonella strains are becoming more antibiotic-resistant, treating the infection is more difficult,” said VIDO-InterVac scientist Aaron White, U of S Jarislowsky Chair in Biotechnology.
“Developing a vaccine will reduce the need for antibiotics and may slow down the development of antibiotic-resistant strains.”
Salmonella infection causes gastroenteritis which involves vomiting, fever and diarrhea. People can get infected by eating contaminated meat, eggs, or milk, or when foods have come into contact with manure. Pets such as cats, dogs, and reptiles may also carry and spread the infection.
White’s PhD student Akosiererem Sokaribo has genetically modified a salmonella strain to generate a new variant that produces high quantities of the vaccine antigen, a molecule that induces immune responses to the bacteria.
“Our vaccine may be unique for its potential to protect against multiple salmonella strains because it relies on an antigen that is common to the strains that cause gastroenteritis,” said Sokaribo, a student who has come from Nigeria to VIDO-InterVac for the opportunity to work at a world-class institute for infectious diseases and vaccine research.
“With more than 1,500 salmonella variants causing gastroenteritis, so far it has been difficult for researchers to develop a vaccine that could work for all,” she said.
Sokaribo has tested the novel vaccine on more than 50 healthy mice to determine whether their immune systems were activated. All animals showed a strong immune response to the vaccine.
“This is a very good sign. If we didn’t get any immune response, it means the vaccine would not work,” said Sokaribo.
She presented her results on June 25th at the fifth International One Health Congress in Saskatoon, organized by the U of S and the One Health Platform.
The team’s next step is to test the efficacy of the vaccine in protecting mice against salmonella infection, and they hope they will complete the new trials by the end of 2018.
Even though it was a preliminary trial, Sokaribo said the testing was a success because she was able to purify the antigen in large quantities. This means potential costs could be reduced if the vaccine enters production.
“Delivering a low-cost vaccine is important, especially in low-income countries where salmonella remains a huge burden,” said White.
The researchers’ vaccine potentially targets both humans and animals. The work is an example of the U of S excellence in One Health research that focuses on the interconnectedness of human, animal and environmental health.
The project has been funded by the federal Natural Sciences and Engineering Research Council (NSERC), the Saskatchewan Health Research Foundation (SHRF), and the Jarislowsky Chair in Biotechnology through combined funding from the U of S, the Saskatchewan government and Stephen Jarislowsky, a Montreal businessman who has established a philanthropic legacy of supporting research in Canada.
Federica Giannelli is a graduate student intern in the University of Saskatchewan research profile and impact unit. This article first ran as part of the 2018 Young Innovators series, an initiatvie of the U of S Research Profile and Impact Office in partnership with the Saskatoon StarPhoenix.