Literature Search Strategy

A limited literature search was conducted on key resources including PubMed, The Cochrane Library, University of York Centre for Reviews and Dissemination (CRD) databases, ECRI, Canadian and major international health technology agencies, as well as a focused Internet search. No filters were applied to limit the retrieval by study type. Where possible, retrieval was limited to the human population. The search was also limited to English language documents published between January 1, 2005 and June 2, 2015.

Selection Criteria and Methods

One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.

Table 1

Selection Criteria.

Exclusion Criteria

Studies were excluded if they did not satisfy the selection criteria, if they were duplicate publications, or were published prior to 2005. Studies reporting sensitivity of a particular method by confirming only the positive test results with another method were excluded. Studies already included in an included health technology assessment or systematic review, were excluded. Studies on the identification of multiple organisms that did not report results separately for STEC were excluded.

Critical Appraisal of Individual Studies

Critical appraisal of a study was conducted based on an assessment tool appropriate for the particular study design. The AMSTAR checklist¹² was used for systematic reviews; the QUADAS 2 tool¹³ for diagnostic studies; the British Medical Journal checklist¹⁴ for economic studies and the AGREE II tool¹⁵ for evidence-based guidelines.

For the critical appraisal, a numeric score was not calculated. Instead, the strength and limitations of the study were described narratively.