Fourth external quality assessment scheme for typing of verocytotoxin-producing E.coli (VTEC)

​External quality assessment (EQA) schemes enable laboratories to assess their methods and procedures so that sources of systematic and random errors can be identified, eliminated, or reduced. Thus, an EQA also improves the accuracy of national and EU-level surveillance. This report presents the results of the fourth round of the VTEC external quality assessment scheme for the typing of verocytotoxin-producing E. coli (VTEC). The fourth EQA was carried out from November 2012 to February 2013 and included the following methods: pulsed-field gel electrophoresis (PFGE), O:H serotyping, detection of virulence genes (eae, vtx1, vtx2 and ehxA), subtyping of the vtx genes, phenotypic detection of verocytotoxin/Shiga toxin production (VT/Stx), fermentation of sorbitol, production of β-glucuronidase, enterohaemolysin, and extended β-lactamase (ESBL). Overall results were good. However, there are a few European laboratories which could benefit from a review of their in-house procedures and protocols.