Table 5.

Proposed^* molecular approach for the categorisation of VTEC (vtx present)

Group	Genes†	Serogroups	Potential risk‡	HUS/HC§
			Diarrhoea
I	eae-positive or (aaiC and aggR)-positive	O157, O26, O103, O145, O111, O104	High	High
II	eae-positive or (aaiC and aggR)-positive	Any other	High	Unknown
III	eae-negative and (aaiC plus aggR)-negative	Any other	Unknown	Unknown

^*As yet this proposed molecular approach must be regarded as provisional. This is because screening VTEC for the presence of eae, aaiC and aggR is not routinely undertaken by all laboratories reporting data to The European Surveillance System.

^†Additional to the presence of vtx genes. eae, Intimin-coding gene; aaiC, chromosomally encoded gene encoding secreted protein of EAEC; aggR, plasmid-encoded regulator gene.

^‡Needs epidemiological studies for confirmation.

^§HUS, Haemolytic uraemic syndrome; HC, haemorrhagic colitis.