An investigation of Salmonella Typhimurium and monophasic variants isolated from Canadian shellfish

Funding period: 2020-2024
Lead: Lisa Hodges
Total GRDI funding: $13,000

Salmonella is one of the most common causes of food-borne bacterial gastroenteritisworldwide and has been associated with a wide range of food types, including raw shellfish. In Canada, the CFIA routinely tests raw shellfish for the presence of Salmonella and, unlike non-shellfish foods, the isolates recovered are almost exclusively S. Typhimurium and its monophasic variant (I 4,[5],12:i:), based on whole genome sequencing. This project focuses on better understanding the Salmonella population that appears to be almost exclusive to raw shellfish in Canada. The objectives are to: 1) evaluate whether S. Typhimurium and monophasic variants are more likely to survive in marine environments compared to other serovars, 2) determine whether current approaches to regulatory testing limit our ability to identify multiple strains in a single sample, and 3) develop a typing method based on single nucleotide polymorphisms to allow for differentiation of S. Typhimurium and its monophasic variants (and potentially between strains). Results will inform traceback investigations by conclusively linking a product to an outbreak.