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Shiga-toxin (verocytotoxin) producing Escherichia coli identification

Enteric Reference Laboratory



Health Science

Lab name

Enteric Reference Laboratory

Lab location

Wallaceville Science Centre, Upper Hutt

Test name

Escherichia coli shiga-toxin gene detection and serotyping


E. coli

Requested for surveillance


Notice required


Routine turnaround time

10 days

Sample requirements

Pure culture. Mixed cultures may be referred for toxin testing if VTEC infection is suspected and the case meets the specimen requirement criteria 

Specimen requirements 

Serum (~1 mL) collected within 7 days of illness onset

Urine (~50 mL) collected within 15 days of illness onset

Media requirements

Nutrient agar slope for cultures

Pre-transport requirements

Ambient temperature

Transport requirements

Ambient temperature

Unacceptable sample types

Mixed cultures will not be tested

How results reported

E. coli isolate with stx gene(s): Serotype, stx subtype, and eae and hylA gene presence reported. stx negative: the isolate will be reported as negative for verocytotoxin. confirmed toxin positive but not isolated: reported as verocytotoxin positive.

Referral link