Verotoxigenic Escherichia coli (VTEC) are a significant cause of bacterial foodborne illness in Canada and worldwide. There are a number of different types of pathogenic E. coli (pathotypes), but VTEC are the only E. coli pathotype that is nationally notifiable in Canada. The public health significance of VTEC is due to the high infectivity of some strains, the potential for life-threatening illness and the limited treatment options available. However, it is recognised that differences in the virulence potential among VTEC strains exist, and the clinical outcomes reported for this group of pathogens ranges from severe to mild.
In Canada, Whole Genome Sequencing (WGS) is becoming an important method for the characterisation of bacterial pathogens, including VTEC, by those authorities concerned with public health and food safety. Genomic characterisation of bacterial isolates by WGS offers a number of advantages over the established mix of molecular and phenotypic methods used for isolate characterisation, notably once the wet laboratory chemistry work of isolate sequencing has been completed, diverse genomic traits can be assessed through computational analysis. This offers significant savings to the cost and time of isolate characterisation. Additionally, subtyping utilising WGS data can potentially offer a high level of discrimination. Consequently, the expanded use of WGS data analysis offers opportunities to improve human foodborne disease surveillance, outbreak response, health risk assessment and regulatory food sampling.
The purpose of this document is to assist federal health portfolio food safety partners (FFSP) with the utilisation of genomic data for the characterisation of VTEC and to support those researchers seeking to develop and apply genomic characterisation of VTEC for the purposes of food safety. To this end, this document includes a summary of established information regarding VTEC as foodborne pathogens, presented within the context of the regulatory and data collection activities of the FFSP. By providing both summary and context this document will assist FFSP in identifying knowledge gaps which might be addressed through further research and improved data collection practices.