Regional differences in presence of Shiga toxin-producing Escherichia coli virulence-associated genes in the environment in the North West and East Anglian regions of England.

E Kintz,S.J O’Brien,N.J Williams,I.R Lake,P.R Hunter,M Es,N Jones

doi:10.1111/lam.13303

Abstract

Shiga toxin-producing Escherichia coli is carried in the intestine of ruminant animals, and outbreaks have occurred after contact with ruminant animals or their environment. The presence of STEC virulence genes in the environment was investigated along recreational walking paths in the North West and East Anglia regions of England. In all, 720 boot sock samples from walkers' shoes were collected between April 2013 and July 2014. Multiplex PCR was used to detect E. coli based on the amplification of the uidA gene and investigate STEC-associated virulence genes eaeA, stx1 and stx2. The eaeA virulence gene was detected in 45·5% of the samples, where stx1 and/or stx2 was detected in 12·4% of samples. There was a difference between the two regions sampled, with the North West exhibiting a higher proportion of positive boot socks for stx compared to East Anglia. In univariate analysis, ground conditions, river flow and temperature were associated with positive boot socks. The detection of stx genes in the soil samples suggests that STEC is present in the English countryside and individuals may be at risk for infection after outdoor activities even if there is no direct contact with animals. SIGNIFICANCE AND IMPACT OF THE STUDY: Several outbreaks within the UK have highlighted the danger of contracting Shiga toxin-producing Escherichia coli from contact with areas recently vacated by livestock. This is more likely to occur for STEC infections compared to other zoonotic bacteria given the low infectious dose required. While studies have determined the prevalence of STEC within farms and petting zoos, determining the risk to individuals enjoying recreational outdoor activities that occur near where livestock may be present is less researched. This study describes the prevalence with which stx genes, indicative of STEC bacteria, were found in the environment in the English countryside.

Highlights

Shiga toxin-producing E. coli cause diarrhea, often bloody, that can progress to anaemia and kidney failure
The aim of this research was to analyse boot socks generated during the Enigma project for Campylobacter to determine the frequency with which STEC-associated virulence genes were detected in the English countryside (Jones et al, 2017)
If the virulence genes detected on these walks are associated with live bacteria, these results indicate there would be the possibility for these strains to cause potentially severe disease if individuals became infected

Summary

Introduction

Shiga toxin-producing E. coli cause diarrhea, often bloody, that can progress to anaemia and kidney failure. The first outbreak of STEC was attributed to ground beef patties at a fast food restaurant chain in the United States in 1982 (Riley et al, 1983), and meat products are still associated with causing many STEC outbreaks (Heiman et al, 2015, Adams et al, 2016). All published case-control studies performed on sporadic infections within the UK have identified contact with animals or their environments as a significant contributor to sporadic infections (Kintz et al, 2017). A recent study reports significant associations between livestock density and the spatial distribution of STEC infections in England (Elson et al, 2018). All this raises interesting questions about the likelihood of acquiring a STEC infection by participating in recreational outdoor activities in the countryside

Objectives

Methods

Results

Conclusion