Meet the Jury Aaron White on New Tools to Study Interactions Between Salmonella and Their Hosts

When internationally renowned experts visit KU Leuven as a member of a PhD Examination Committee, we like to seize this opportunity to give this expert a forum to a large audience. All members of Science, Engineering & Technology are most welcome to the Meet The Jury Lectures.

Prof. Aaron White (University of Vienna, Austria) will give a lecture on “New Tools to Study Interactions Between Salmonella and Their Hosts”.

Abstract:
Non-typhoidal Salmonella are a leading cause of foodborne illness. These bacteria cycle between infecting hosts and persisting in nature as biofilms. The host-to-environment transition of Salmonella is a critical stage in the transmission cycle that is not well understood. In non-typhoidal Salmonella, bistable synthesis of the master biofilm regulator CsgD results in a population of CsgD⁺ biofilm aggregates and CsgD⁻ single cells that synthesize the Salmonella pathogenicity island 1 type III secretion system (SPI-1 T3SS), which facilitates host cell invasion. We hypothesize that population splitting is a bet-hedging strategy that improves the odds of transmission, providing a path to cause disease immediately (single cells) and a path to survive for long time periods (biofilms). We have built a “dual fluorescent reporter” strain of S. Typhimurium that tracks biofilm⁺ cells (GFP) and SPI-1 T3SS⁺ cells (mCherry) simultaneously. We quantified four distinct cell populations in a biofilm flask model: CsgD⁺/SPI-1⁻, CsgD⁻/SPI-1⁺, CsgD⁺/SPI-1⁺, CsgD⁻/SPI-1⁻, and have investigated the dynamics of infections inside Caenorhabditis elegans worms. The use of this dual-reporter strain will provide a unique way to study different Salmonella cell types in real-time. I will discuss different theories on bet-hedging, how it relates to the types of Salmonella infections and how it might impact their hosts.

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