STEC / VTEC

Question 1

What is STEC?

Answer 1

Shiga-toxin producing E. coli

Question 2

Is STEC nationally notifiable?

Answer 2

Yes - routine, labs and doctors

Question 3

What organism causes STEC?

Answer 3

EHEC - enterohaemorrhagic E. coli
Many serotypes described by O and H antigens

Question 4

What is the reservoir for STEC?

Answer 4

Animals (esp cattle) and the environment

Question 5

How is STEC transmitted?

Answer 5

• Faecal-oral via contaminated food/water (esp. undercooked meat, unpasteurised milk, unwashed produce)
• Person-to-person
• Zoonotic - animal-to-person
• Fomites

Question 6

What are the clinical features?

Answer 6

Spectrum - Asx, mild, severe

Diarrhoea (bloody), abdominal pain, N/V, fever
Usually self-limiting (1 week)

Question 7

What are complications of STEC?

Answer 7

HUS - haemolytic uraemic syndrome
TTP
Stroke/seizures
Bowel ischaemia/perforation

Question 8

Who are high-risk groups for severe disease from STEC?

Answer 8

Children < 5yo
Elderly
Immunocompromised

Question 9

Who are high risk groups for acquisition?

Answer 9

Occupational exposure to animals/red meat, farms, camping

Question 10

What are the case definitions for STEC?

Answer 10

Confirmed only (culture or PCR)

Question 11

How is STEC diagnosed?

Answer 11

PCR (stx1 and stx2 gene)
Culture

Need to specifically request - all samples sent to MDU for further testing; WGS if culture positive

Question 12

What is the incubation period for STEC?

Answer 12

2-10 days (average 3-4)

Question 13

What is the infectious period for STEC?

Answer 13

While present in faeces (median 18 days)
Can be up to 4-6 weeks (usually shorter in adults vs. kids)

Question 14

What is the outbreak definition of STEC?

Answer 14

Single case potentially indicative
2 or more cases depending on the setting

Cluster = increase in cases related to TPP or genomic with no known common source

Question 15

T/F: most cases are sporadic?

Answer 15

True

Question 16

What proportion of cases develop HUS?

Answer 16

3%

Question 17

Which settings are local outbreaks associated with?

Answer 17

Food, petting zoos, camps, swimming areas, childcare

Local OBs uncommon

Question 18

How can STEC be prevented?

Answer 18

Hygiene
Food safety

Question 19

What resources are available for the public health management of STEC?

Answer 19

DH protocol. No SoNG.
Various gastro guidelines

Question 20

How are cases of STEC managed?

Answer 20

Clinician - call
Case interview - DRSVECTA: food hx, high-risk settings
Active case finding - if case food handler, CC, RCF, HCW

T - treating clinician
I - exclude while infectious if food handler, CC, RCF, HCW; 24hrs post diarrhoea for primary/ECEC; 48hrs if food handler, HCW, CC worker
E - transmission, hygiene, animal contact, safe food practices (e.g. avoid undercooked meat, washing, no preparing food while infectious)

Individual risk assessment if food handler works in CC, RCF, HCW

Question 21

Who are considered contacts of STEC cases?

Answer 21

HH
People cared for by case
Shared exposure (co-exposed)

Question 22

How are contacts of STEC managed?

Answer 22

T - if Sx arrange testing
I - exclude if symptomatic
E - sx, transmission, hygiene

Question 23

What environmental managed is required for STEC?

Answer 23

Cleaning advice for home
Discarding food items handled by the case
Food premised, childcare - environmental clean of facility
Involve council EHOs

Question 24

If the suspected source is food, what should be done?

Answer 24

• Involve OzFoodNet
• Involve Food Safety Unit
• Consider trace back
• Site inspection
• Sampling - council EHOs

Food source rare

Question 25

If the suspected source is water, what should be done?

Answer 25

* Involve Water Unit / OzFoodNet * Council EHOs is private source - inspection, water providers, sampling ## Footnote Water source rare

Question 26

If the suspected source is an animal, what should be done? ## Footnote E.g. petting zoo

Answer 26

Council EHOs - inspection, sampling (faeces, environment)