Knowledge Gaps and Research Agenda

In view of the foregoing considerations a number of important questions remain which might be answered through targeted research aiming to optimize regulatory responses to the occurrence of VTEC in the food supply:

VTEC Virulence Markers

Verotoxin (stx, vt), intimin (eae), and aggregative adhesion (aggR, aaiC) have established roles in VTEC disease processes. What are the roles of other genomic markers in VTEC disease processes?
How should additional genomic markers be identified and interpreted?
What is the biological significance of vt and eae subtypes?

Subtyping of VTEC Isolates

How should subtyping markers (serotype, wgMLST, etc.) be interpreted in evaluating VTEC isolates?
What are the objectives of routine subtyping and how is novel methodology determined to be "fit for purpose"?
Should historical data/isolates be sequenced and analyzed? How could this data be used for risk assessment and risk mitigation?

VTEC Exposure

What is the significance of VTEC loads in various food commodities?
Considering the high infectivity of some VTEC, do low loads contribute to the sporadic distribution of cases?


What is the true burden of human illness related to non-O157 VTEC infections in Canada?
Do current monitoring programs for VTEC in food provide the information required in a cost effective manner? Are there significant gaps in the products or sectors currently being monitored? Can information sharing be improved? What is the best approach for data and information sharing among multi-jurisdictional regulatory partners (e.g., leveraging established network initiatives such as the Canadian Food Safety Information Network, or creating new networks).


What methodological improvements are required? What is the best approach for the identification of risk markers, such as verotoxin subtypes or variants, using WGS techniques (e.g., assembly-dependent/-independent approaches, translation of sequence data and identification of definitive amino acids)?
What are the limitations of determining gene markers on the basis of sequence data given the occurrence of complex nucleotide polymorphism patterns and the discovery of possible novel variants?
What is the potential of predictive genomics in determining biological functionality and informing techniques for the recovery of VTEC? How should culture-independent testing be applied and the results assessed in the context of food safety investigations?

Standards and Guidance

Is there a need to develop new or update standards and guidance related to VTEC in foods?
Should such standards include serotype? What virulence markers should be used?