VTEC/STEC E. coli in Drinking Water Information:

Properties:

Bacteria such as E. coli are a concern in drinking water because they indicate that faecal matter or other harmful pathogens may be present. While many strains of E. coli are harmless and live peacefully in our intestines, there are several strains that are pathogenic and impact human health. VTEC E. coli (also known as STEC, verotoxin/verocytotoxin-producing, Shiga toxin-producing, or Shigatoxigenic E. coli) is a form of the bacteria that produces a poison called Shiga toxin or verotoxin.1

Sources:

In general, the predominant route for human exposure is consumption of contaminated meat—foodborne illness is a major concern with regard to this particular strain of E. coli. However, faecal matter or run-off from farmland can also reach raw water supplies and contaminate drinking water.2 Improper wastewater treatment, inefficient disinfection, and raw water contamination are all factors in the spread of VTEC E. coli.

Regulations:

The limit for E. coli in drinking water is 0/100 mL (millilitres).

Health/Environmental Concerns:

VTEC E. coli bacteria cause a range of gastrointestinal symptoms including abdominal cramps, diarrhoea, bloody diarrhoea, and in severe cases haemolytic uraemic syndrome (HUS).2 In general, symptoms do not persist longer than 5-7 days.3 However, haemolytic uraemic syndrome can be quite serious; it causes damage to blood vessels in the kidneys that may lead to clotting or kidney failure.4

Action:

The most effective way to prevent infection by VTEC E. coli is to monitor and regulate water quality at its source. Faecal matter and contaminated run-off from farmland should not be present in drinking water supplies. If drinking water does become contaminated, usage should be discontinued until proper, effective disinfection procedures have been put in place. If you suspect that your drinking water supply is contaminated, contact your Water Service Authority. If drinking water makes you feel ill, contact a doctor right away.

1 Joint FAO/WHO Core Expert Group Meeting on VTEC/STEC: Meeting Report. Food and Agriculture Organization of the United Nations; World Health Organization: Geneva, Switzerland, 19-22 July, 2016.

2 Factsheet: VTEC. Health Protection Surveillance Centre: Dublin, Ireland; 19 July, 2018.

3 Questions and Answers: E. coli (Escherichia coli). Centers for Disease Control and Prevention; Department of Health & Human Services: United States, 1 Dec, 2014.

4 Patient Care & Health Info: Hemolytic uremic syndrome (HUS). Mayo Clinic; Mayo Foundation for Medical Education and Research (MFMER): United States, 2020.