Vaccine and Infectious Disease Organization -
International Vaccine Centre

Salmonella biofilm formation, virulence, transmission and vaccine development

Project Leader: Aaron White

Pathogenic Salmonella strains are a prominent cause of human food-borne infections. Despite decades of research, the Salmonella genes responsible for human transmission have not been identified, and it is not well understood in what form this bacterium survives outside the human body. This makes it difficult to design strategies to reduce transmission and prevent infection.

We determined that S. Typhimurium population divergence occurs during biofilm formation, resulting in specialized groups of cells: single cells that are highly virulent and multicellular aggregates that are persistent and can survive long periods of time. This genetic program connects virulence and persistence within the same population of cells and provides a strategy that would enhance transmission, especially under circumstances when Salmonella passes out of an infected host into the environment and faces an uncertain future. The idea that specialized cell types can exist is a new concept and has implications for many aspects of Salmonella research, including the comparison between host-generalist and host-adapted strains, understanding the innate immune response and designing better anti-Salmonella vaccines.


  • Examine differences between host-generalist and host-restricted strains of Salmonella 
  • Identify key factors that control the formation of specialized cell types of S. Typhimurium
  • Production of a traveler’s vaccine for the most common disease-causing Salmonella serovars
  • Examine S. Typhimurium transmission in a murine model and develop genetic tools for use in fluorescence and luminescent imaging