Escherichia coli shiga-toxin gene detection and serotyping
Registry Details
| Area | Health Science |
| Lab name | Enteric Reference Laboratory |
| Lab location | NCBID Wallaceville |
| Test name | Escherichia coli shiga-toxin gene detection and serotyping |
| Organisms | E. coli |
| Requested for surveillance | yes |
| Notice required | no |
| Routine turnaround time | 10 days |
| Culture requirements | Pure culture. Mixed cultures may be referred for toxin testing if VTEC infection is suspected and the case meets the criteria described under the Details section below. |
| 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 | If positive: E. coli serotype and toxin/virulence genes profile. If negative, the isolate will be reported as negative for verocytotoxin. |
| Referral link | Form |
Description
Please refer to this document for a recommended culture process for STEC for stx positive samples.
Details
Changes to STEC/VTEC reference laboratory testing at ESR's Enteric Reference Laboratory
Effective: 15 September 2017
ESR's Enteric Reference Laboratory (ERL) will no longer accept faecal broths or mixed cultures for STEC/VTEC reference testing. ERL will only perform serotyping (and further characterisation) on pure cultures of STEC/VTEC referred by diagnostic laboratories where stx genes have been detected or Shiga toxin/Verotoxin production demonstrated. Exceptions to this will include broths or mixed cultures from “high risk” cases meeting one or more of the following criteria:
- hospital inpatients
- children under 10 years of age
- cases of HUS or TTP
- bloody diarrhoea
- suspected clusters of cases /outbreaks
- history of overseas travel in preceding 14 days
- individual cases where testing is specifically requested by the local medical officer of health
- individual cases upon discussion with an ESR clinical microbiologist or ERL co-ordinator
We would like to emphasise the need for diagnostic laboratories to continue referring STEC/VTEC isolates to ERL for serotyping and further characterisation.
ERL can offer a storage service for PCR positive, culture negative faecal broths referred from diagnostic laboratories. Specimens will be stored for a period of 3 months at -80°C for subsequent testing if requested by the local public health unit or ESR health intelligence team.
Please email any questions or comments you may have to contact jackie.wright@esr.cri.nz