Staff from the HPA have written and contributed to several papers and reports about VTEC, some of which are presented below. The following paragraphs are identical to the abstracts or summaries presented in the papers and reports, and for that reason, there are some differences in the nomenclature.

A case of verocytotoxin-producing Escherichia coli O157 from a private barbecue in South East England

The following case report describes a cluster of Escherichia coli O157 cases in the United Kingdom related to undercooked beef at a barbecue, resulting in an intensive care admission in France with haemolytic uraemic syndrome and highlighting the need to cook beef properly.

The inquiry into the outbreak in South Wales, September 2005

The outbreak of E.coli O157 in South Wales in September 2005 was the largest outbreak caused by this organism in Wales and the second largest to date in the UK. A total of 157 cases were identified, of which 118 were confirmed microbiologically as E.coli O157. Of those, 109 were of a strain unique to the outbreak. Most cases were children in 44 schools across four local authority areas. Thirty-one people
were admitted to hospital and one child died.
The outbreak was caused by food, cooked meats in this case, that had been contaminated with E.coli O157. Extensive microbiological testing and typing revealed that the strains of E.coli O157 in people who were infected were indistinguishable from those found on cooked meats recovered from schools, in a sample of raw meat recovered from the premises of John Tudor & Son, a catering butcher business, and in samples of cattle faeces taken from a farm.

The Chicken Wrap outbreak, July 2007

A national outbreak of verotoxin-producing Escherichia coli O157 infection affected five English regions and Wales. Twelve cases were associated with lemon-and-coriander chicken wrap from a single supermarket chain consumed over a 5-day period. An outbreak investigation aimed to identify the source of infection. Descriptive epidemiology and phenotypic and genotypic tests on human isolates indicated a point-source outbreak; a case-control study showed a very strong association between consumption of lemon-and-coriander chicken wrap from the single supermarket chain and being a case (OR 46.40, 95% CI 5.39-infinity, P=0.0002). Testing of raw ingredients, products and faecal samples from staff in the food production unit did not yield any positive results. The outbreak was probably caused by one contaminated batch of an ingredient in the chicken wrap. Even when current best practice is in place, ready-to-eat foods can still be a risk for widespread infection.

Escherichia coli serogroup O26--a new look at an old adversary

Escherichia coli serogroup O26 played an important part in the early work on verocytotoxin and is an established diarrhoeal pathogen. Recently, Verocytotoxigenic E. coli (VTEC) O26 has been increasingly associated with diarrhoeal disease and frequently linked to outbreaks and cases of haemolytic uraemic syndrome (HUS). This review investigates the pathogenicity, geographical distribution, changing epidemiology, routes of transmission and improved detection of VTEC O26. Laboratory data on VTEC O26 isolates and clinical data on HUS suggest a true difference in the incidence of VTEC O26 in different geographic locations. However, few diagnostic laboratories use molecular methods to detect VTEC and so it is difficult to assess the role of VTEC O26 in causing diarrhoeal disease. VTEC O26 is frequently found in the cattle population but rarely in food. However, the small number of outbreaks analysed to date are thought to be food-borne rather than associated with direct or indirect contact with livestock or their faeces. The increase in awareness of VTEC O26 in the clinical and veterinary setting has coincided with the development of novel techniques that have improved our ability to detect and characterize this pathogen.

The Jigsaw Nursery outbreak in Chester, September 2007

A total of five cases (three children attending the Jigsaw nursery and two adult household contacts) of Vero cytotoxin-producing Escherichia coli (VTEC) O157 phage type (PT) 21/28 occurred in September 2007, and one child developed HUS.  Three potential sources for the outbreak were investigated (the Jigsaw Nursery, an open farm in Lancashire and a private small holding in North Wales).  PFGE profiles of samples (six human, six veterinary, one environmental) collected from the small holding in North Wales were indistinguishable from those seen in the children, suggesting that the small holding was the most likely initial source.

Foodborne general outbreaks of Shiga toxin-producing Escherichia coli O157 in England and Wales 1992-2002: where are the risks?

Between 1 January 1992 and 31 December 2002, Shiga toxin-producing Escherichia coli O157 (STEC O157) accounted for 44 of the 1645 foodborne general outbreaks of infectious intestinal disease reported to the Health Protection Agency Communicable Disease Surveillance Centre. These outbreaks, although rare, were characterized by severe infection, with 169 hospital admissions and five deaths reported. STEC O157 outbreaks were compared with other pathogens to identify factors associated with this pathogen. Single risk variable analysis and logistic regression were employed. Two distinct aetiologies were identified. Foodborne outbreaks of STEC O157 infection in England and Wales were independently associated with farms, which related to milk and milk products, and with red meats/meat products, which highlighted butchers' shops as a cause for concern. The introduction and adherence to effective control measures, based on the principles of hazard analysis, provide the best means of minimizing the risk of foodborne infection with this pathogen.

 

Last modified: 29 July 2009