Risk factors for and prevention of sporadic infections with vero cytotoxin (shiga toxin) producing Escherichia coli 0157

doi:10.1016/S0140-6736(97)08376-1

The Lancet

Volume 351, Issue 9108, 4 April 1998, Pages 1019-1022

https://doi.org/10.1016/S0140-6736(97)08376-1 Get rights and content

Summary

Background

Recent outbreaks of vero cytotoxin (shiga toxin) producing Escherichia coli 0157 (VTEC 0157) infection have stimulated debate on food safety. However, 90% of cases in England and Wales are sporadic. We report a case-control study of sporadic VTEC 0157 infection.

Methods

We compared 85 sporadic cases of VTEC 0157 infection, identified through population surveillance, with 142 controls, randomly selected from general practitioners' lists. We matched cases and controls for age, sex, and family doctor's practice. Exposures to foods, water, animals, farms, and environmental factors were recorded. We visited the premises concerned when cases had eaten beefburgers or cooked sliced meats from caterers or had had contact with a farm.

Findings

Consumption of a beefburger from a catering premises other than from a fast-food chain A (a national chain) and consumption of cold cooked sliced meat (eg, in a salad or sandwich) from caterers, but not butchers, was associated with VTEC 0157 infection (odds ratios 4·63 [95% Cl 1·33–30·14] and 3·36 [1·04–12·74], respectively). Policies for ensuring thorough cooking of burgers by one national fast-food chain differed from the other catering premises we visited. There was evidence of person-to-person spread and transmission of VTEC 0157 infection from animals.

Interpretation

Local inspection of catering establishments that serve cooked meats together with public education to prevent spread on farms and in houses would reduce the burden of VTEC 0157 infection by about 10% for each risk factor.

Introduction

Vero cytotoxin (shiga toxin) producing Escherichia coli, particularly those of serogroup O157 (VTEC O157), are, arguably, the most important emerging foodborne pathogens, with highly publicised outbreaks in Scotland,¹ Japan,² and the USA.³ The resulting debate on food safety has been largely based on knowledge from outbreak reports4, 5 that indicate a bovine reservoir, with transmission via contaminated meat,³ milk,⁶ water,⁷ cooked foods,⁸ and direct spread from animals⁹ and person to person.¹⁰ However, 90% of VTEC O157 infection in England and Wales is sporadic.¹¹ In North America, case-control studies show an association with undercooked beef.12, 13, 14 There have been few population-based case-control studies of sporadic VTEC O157 infection,¹⁴ and our study is the first to report not only food-related risk factors but also risk factors for person-to-person and zoonotic transmission.

Section snippets

Methods

Since 1990, the eight public health laboratories and 11 National Health Service laboratories that serve Wales and the English border counties, have examined all first-time faecal specimens from individuals with acute gastrointestinal symptoms for VTEC O157 with Sorbitol MacConkey agar¹⁵ and latex agglutination with O157 antiserum (Oxoid, BioMerieux Marcy L'Etoile, France). Presumptive E coli O157 were forwarded to the laboratory of enteric pathogens, Central Public Health Laboratory, for

Results

Of 89 cases, 85 (96%) took part in the study. H typing was available for 76 cases, 48 of which were E coli O157:H7 and the remainder were E coli O157:H- (non-motile). 142 (74%) of the 193 controls took part. The median delay between the onset of gastrointestinal illness and interview was 15 (range 3–103) days for cases and 28 (8–134) days for controls.

Discussion

The outbreak of VTEC O157 in Scotland in November, 1996, focused public attention on the food safety, particularly from butchers' shops. The report published after this outbreak recommended a licensing system for premises that sell raw and cooked meat or meat products.⁵ In our study of sporadic VTEC O157 cases, infection was not associated with loose cooked sliced meats from butchers. However, consumption of a cooked sliced meat meal from a caterers (eg, in a sandwich) was associated with

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Cited by (72)

Transmission pathways for sporadic Shiga-toxin producing E. coli infections: A systematic review and meta-analysis
2017, International Journal of Hygiene and Environmental Health
Shiga-toxin E. coli infections remain a public health concern because of the severity of the gastrointestinal illness and associated complications. Transmission pathways are typically elucidated from outbreaks, with foodborne transmission the primary source. However, most STEC cases are sporadic. This systematic review aimed to identify the most common pathways for sporadic STEC transmission and quantify their importance.
We systematically reviewed epidemiological studies of sporadic (non-outbreak) STEC cases that investigated potential risk factors. Searches were run in Medline, EMBASE, and Scopus. Included studies needed to confirm STEC infection and investigate ≥20 cases.
31 studies were included, of which 25 were case-control or case-case studies. 62.5% found consumption of undercooked/raw meat associated with STEC infection while 70.4% found contact with animals or their environment a risk factor. Random-effects meta-analysis provided pooled odds ratios and population attributable fraction (PAF). The PAF was 19% for undercooked/raw meat, followed by person to person transmission at 15%. Contact with animals and visiting farm environments had PAFs of 14% and 12% respectively.
Out of potential sources for STEC exposure, undercooked meat and contact with animals and their environment were the most frequently found transmission routes. Decreasing the chances of acquiring the bacteria by these methods would additionally cut down on the other major transmission route, person-to-person spread.
Bacterial Zoonoses: An Overview
2014, Molecular Medical Microbiology
During this overview, we explore some of the conundrums of zoonoses. These range from defining what we actually mean by the term zoonoses, through to understanding the driving forces that facilitate emergence of new or promote the re-emergence of known zoonoses. In an attempt to embrace the complexity of these factors, we are now encouraged to take a holistic one-health approach whereby environmental, wildlife, veterinary, medical and social factors are considered collectively. Understandably, such intricate intertwined factors make it difficult to accurately model and predict the emergence and spread of infections. Despite the research investment into pathogen discovery, and prediction of expanding geographical ranges of known bacterial zoonoses, sadly little is done to control or reduce some of the major bacterial zoonoses such as brucellosis and leptospirosis. These have their largest impact upon those in resource-poor settings where these infections are endemic and their effects are profound.
Hemolytic Uremic Syndrome
2008, Comprehensive Pediatric Nephrology: Text with CD-ROM
Hemolytic Uremic Syndrome
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Escherichia coli O157: Burger bug or environmental pathogen?
2006, International Journal of Food Microbiology
The three main pathways of Escherichia coli O157 infection are foodborne, environmental (including direct contact with animals and their faeces and contaminated water supplies) or person to person contact. The disease is often nicknamed the ‘burger bug’ but it appears that environmental risk factors may be more important. In this study we use four techniques (outbreak analysis, case–control studies, disease mapping and quantitative microbial risk assessment (QMRA)) to determine whether burgers or environmental pathways present the greater risk in Scotland. Analysis of E. coli O157 outbreaks in Scotland from 1994 to 2003 associated with either meat or dairy foods, or with environmental transmission shows that approximately 40% [M1] of these outbreaks were foodborne, 54% were environmental and 6% involved both transmission routes. However, the largest outbreaks tend to be foodborne accounting for 83% of outbreak cases. Case–control studies indicate strong risk associations with environmental exposure in Scotland, the UK as a whole and the USA, but burgers appear to be more of a risk in the USA. Canadian, Scottish and Swedish disease mapping studies found positive association with indicators of cattle density. In Grampian (North-East Scotland) we found that there was a positive association with cattle and sheep density (divided by human population density) as well as percentage of population on private water supplies. We found 63% of cases in rural postcodes compared with 37% urban after correcting for population differences suggesting that at least 26% of cases may be classified as environmental. QMRA showed that on average, the risk was 100 times greater when visiting a pasture than eating a burger in Grampian. However, it is difficult to determine which pathway actually causes most illnesses as it is unknown how many burgers are consumed daily and what is the frequency of human visits to pasture. The implementation of hygienic food processing post-1996 Central Scotland outbreak and the preference for ‘well done’ burgers may account for this food being a relatively low risk thus making the ‘burger bug’ term less appropriate in the UK.
Verotoxigenic Escherichia coli transmission in Ireland: A review of notified outbreaks, 2004-2012
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The Lancet

Summary

Background

Methods

Findings

Interpretation

Introduction

Section snippets

Methods

Results

Discussion

References (21)

Waterborne outbreak of Escherichia coli O157

Lancet

Haemorrhagic colitis in child after visit to farm visitor centre

Lancet

E coli O157 in Scotland

SCIEH Wkly Rep

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 infection, 1996, Japan

Infect Agents Surveill Rep

Preliminary report: foodborne outbreak of Echerichia coli O157:H7 infections from hamburgers—Western United States

MMWR CDC Surveill Summ

Report on Verocytotoxin-producing Escherichia coli.

Report of the circumstances leading to the 1996 outbreak of infection with E coli O157 in Central Scotland, the implications for food safety and the lessons to be learned

Untreated milk as a source of verotoxigenic Escherichia coli O157

Vet Rec

Outbreak of Escherichia coli O157 phage type 2 infection associated with eating cooked sliced meats

Commun Dis Rep CDR Rev

Escherichia coli O157 infection associated with a farm visitor centre

Commun Dis Rep CDR Rev

Cited by (72)

Transmission pathways for sporadic Shiga-toxin producing E. coli infections: A systematic review and meta-analysis

Bacterial Zoonoses: An Overview

Hemolytic Uremic Syndrome

Hemolytic Uremic Syndrome

Escherichia coli O157: Burger bug or environmental pathogen?

Verotoxigenic Escherichia coli transmission in Ireland: A review of notified outbreaks, 2004-2012

ArticlesRisk factors for and prevention of sporadic infections with vero cytotoxin (shiga toxin) producing Escherichia coli 0157

Summary

Background

Methods

Findings

Interpretation

Introduction

Section snippets

Methods

Results

Discussion

Lancet

Lancet

E coli O157 in Scotland

SCIEH Wkly Rep

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 infection, 1996, Japan

Infect Agents Surveill Rep

Preliminary report: foodborne outbreak of Echerichia coli O157:H7 infections from hamburgers—Western United States

MMWR CDC Surveill Summ

Report on Verocytotoxin-producing Escherichia coli.

Report of the circumstances leading to the 1996 outbreak of infection with E coli O157 in Central Scotland, the implications for food safety and the lessons to be learned

Untreated milk as a source of verotoxigenic Escherichia coli O157

Vet Rec

Outbreak of Escherichia coli O157 phage type 2 infection associated with eating cooked sliced meats

Commun Dis Rep CDR Rev

Escherichia coli O157 infection associated with a farm visitor centre

Commun Dis Rep CDR Rev

Articles
Risk factors for and prevention of sporadic infections with vero cytotoxin (shiga toxin) producing Escherichia coli 0157